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CVE Vendors Products Updated CVSS v3.1
CVE-2026-68204 1 Linux 1 Linux Kernel 2026-08-19 7.8 High
In the Linux kernel, the following vulnerability has been resolved: media: vivid: check for vb2_is_busy() when toggling caps The vivid_update_format_cap/out() functions must only be called if the capture/output queue are not busy. But for the controls that select the CROP/COMPOSE/SCALE capability that is not checked. Only when streaming starts will they be set to 'grabbed' and it is impossible to change the control, but between REQBUFS and STREAMON you are still allowed to set these controls. Since vivid_update_format_cap/out will change the format, this can cause unexpected results. Besides adding these checks, also add a WARN_ON in vivid_update_format_cap/out() if the queue is busy. I'm 90% certain that this is the cause of this syzbot bug: https://syzkaller.appspot.com/bug?extid=dac8f5eaa46837e97b89 But since we never have reproducers, it is hard to be certain. In any case, these checks are needed regardless.
CVE-2026-68196 1 Linux 1 Linux Kernel 2026-08-19 8.3 High
In the Linux kernel, the following vulnerability has been resolved: wifi: wilc1000: validate assoc response length before subtracting header wilc_parse_assoc_resp_info() computes the trailing IE length as ies_len = buffer_len - sizeof(*res); without first checking that buffer_len is at least sizeof(struct wilc_assoc_resp) (6 bytes). buffer_len is the length reported for a received association response (host_int_parse_assoc_resp_info() passes hif_drv->assoc_resp / assoc_resp_info_len straight in) and must be validated before the driver accesses the fixed header. For a frame shorter than the 6-byte fixed header, the subtraction wraps. For a four-byte response the result is truncated to a u16 ies_len of 65534, so kmemdup() then attempts to copy 65534 bytes starting at buffer + sizeof(*res), beyond the valid association-response data (CWE-125). A response shorter than four bytes can also cause an out-of-bounds read of res->status_code at offsets 2 and 3. Reject frames too short to hold the fixed header before touching the header or computing ies_len. Also set the connection status to a failure on this path: the caller falls through to a "conn_info->status == WLAN_STATUS_SUCCESS" check after the parser returns, so leaving the status untouched could let a malformed short response be treated as a successful association.
CVE-2026-68195 1 Linux 1 Linux Kernel 2026-08-19 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7615: drop TXRX_NOTIFY on non-mmio buses PKT_TYPE_TXRX_NOTIFY is an mmio-only event, but mt7615_rx_check() and mt7615_queue_rx_skb() dispatch it to mt7615_mac_tx_free() on every bus. mt7615_mac_tx_free() cleans the DMA tx queues with mt76_queue_tx_cleanup(), which calls queue_ops->tx_cleanup(). Only the mmio queue ops implement that callback; on the mt7663 USB and SDIO buses it is NULL, so a TXRX_NOTIFY there calls a NULL pointer in the RX worker. Same defect as the mt7921 and mt7925 patches in this series. Drop the event on non-mmio buses via mt76_is_mmio(), as in commit 5683e1488aa9 ("wifi: mt76: connac: do not check WED status for non-mmio devices").
CVE-2026-68194 1 Linux 1 Linux Kernel 2026-08-19 4.8 Medium
In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7921: drop TXRX_NOTIFY on non-mmio buses PKT_TYPE_TXRX_NOTIFY is an mmio-only event, but mt7921_rx_check() and mt7921_queue_rx_skb() dispatch it to mt7921_mac_tx_free() on every bus. mt7921_mac_tx_free() cleans the DMA tx queues with mt76_queue_tx_cleanup(), which calls queue_ops->tx_cleanup(). Only the mmio queue ops implement that callback; on USB and SDIO it is NULL, so a TXRX_NOTIFY there calls a NULL pointer in the RX worker: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:0x0 Call Trace: mt7921_mac_tx_free+0x64/0x310 [mt7921_common] mt7921_rx_check+0x5f/0xf0 [mt7921_common] mt76u_rx_worker+0x1b9/0x620 [mt76_usb] Drop the event on non-mmio buses via mt76_is_mmio(), as in commit 5683e1488aa9 ("wifi: mt76: connac: do not check WED status for non-mmio devices").
CVE-2026-68183 1 Linux 1 Linux Kernel 2026-08-19 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: firmware: stratix10-svc: fix memory leaks and list corruption bugs Fix a memory leak when gen_pool_alloc() fails by freeing pmem on the error path. Switch pmem allocation from devm_kzalloc() to kzalloc() with explicit kfree() in the free path to match its list-managed lifetime. Remove the erroneous list_del(&svc_data_mem) which corrupted the list head on failed lookups.
CVE-2026-68182 1 Linux 1 Linux Kernel 2026-08-19 4.4 Medium
In the Linux kernel, the following vulnerability has been resolved: comedi: comedi_parport: deal with premature interrupt Syzbot reported a general protection fault in `comedi_get_is_subdevice_running()`, which was called from the interrupt handler `parport_interrupt()` in the "comedi_parport" driver, but it does not currently have a C reproducer for the problem. It's probably due to a premature interrupt for one of two reasons: 1. The driver sets up the interrupt handler before the comedi subdevices used by the interrupt handler have been allocated, but does not disable the interrupt in the parallel port's CTRL register first. 2. The driver uses a user-supplied I/O port base address which Syzbot would have supplied, but it might not be backed by real parallel port hardware. Change the initialization order in the driver's comedi "attach" handler (`parport_attach()`) so that the hardware registers are initialized before the interrupt handler is requested. This should prevent premature interrupts occurring for real hardware. Also add a test to the interrupt handler to ensure the comedi device is fully attached and return early if it isn't.
CVE-2026-68176 1 Linux 1 Linux Kernel 2026-08-19 4.4 Medium
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev If the mmio_pipe_open() fails to find a PCI device, the hiter->dev will be assigned to NULL. The mmiotrace read() function dereferences the hiter->dev if hiter exists. Change the test of the read to not only check hiter being NULL, but also the hiter->dev before dereferencing it.
CVE-2026-68175 1 Linux 1 Linux Kernel 2026-08-19 4.4 Medium
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix resource leak on mmiotrace trace_pipe close The mmiotrace tracer was added May 12th 2008. At that time, resources created in pipe_open() could not be freed because there was not pipe_close function pointer of the tracer. The pipe_close function pointer was added in December 7th, 2009, but the mmiotrace tracer was not updated. mmio_pipe_open() allocates a header_iter and takes a pci_dev reference when trace_pipe is opened. mmio_close() frees them, but it was only wired to the tracer's .close callback. tracing_release_pipe() invokes .pipe_close, not .close, when the trace_pipe file is released. As a result, closing trace_pipe with the mmiotrace tracer active leaked the header_iter allocation and left a stale pci_dev reference. Set .pipe_close to mmio_close, matching how function_graph wires both callbacks to the same handler. Note, if the trace_pipe is read to completion, it will clean up the resources, but if one were to run: # head -n 1 /sys/kernel/tracing/trace_pipe VERSION 20070824 Over and over again, it would trigger a massive leak.
CVE-2026-68151 1 Linux 1 Linux Kernel 2026-08-19 N/A
In the Linux kernel, the following vulnerability has been resolved: binfmt_elf_fdpic: only honour the first PT_INTERP The program header scan handles PT_INTERP from a switch nested in the scan loop, so its break leaves the switch and not the loop. A binary carrying more than one PT_INTERP runs the case again and overwrites both interpreter_name and interpreter. The previous name allocation leaks and so does the previous interpreter reference, along with the write denial open_exec() took on it. The denial is never released, so the file stays unwritable for as long as the system runs. An unprivileged caller reaches this with a crafted binary and repeats it at will. binfmt_elf stops at the first PT_INTERP. Do the same here. The flaw dates back to the driver's introduction in the pre-git history tree introduced in v2.6.11 by 91808d6ebe39 ("[PATCH] FRV: Add FDPIC ELF binary format driver").
CVE-2026-68147 1 Linux 1 Linux Kernel 2026-08-19 7.8 High
In the Linux kernel, the following vulnerability has been resolved: fscrypt: Avoid dynamic allocation in fscrypt_get_devices() When a blk_crypto_key starts being used or is evicted, fs/crypto/ calls fscrypt_get_devices() to get the filesystem's list of block devices, then iterates over them and calls blk_crypto_config_supported(), blk_crypto_start_using_key(), or blk_crypto_evict_key() on each one. Currently, the block device pointers are placed in a dynamically allocated array. This dynamic allocation is problematic because: - It can fail, especially at the fscrypt_destroy_inline_crypt_key() call site when it's invoked for inode eviction under direct reclaim. - fscrypt_destroy_inline_crypt_key() doesn't handle the failure. It just zeroizes and frees the blk_crypto_key without calling blk_crypto_evict_key(). That causes a use-after-free. For now, let's fix this in the straightforward and easily-backportable way by switching to an on-stack array. Currently the fscrypt multi-device functionality is used only by f2fs, which has a hardcoded limit of 8 block devices. An on-stack array works fine for that. (Of course, this solution won't scale up to large number of block devices. For that we'd need a different solution, like moving the block device iteration into the filesystem. Or in the case of btrfs, which will only support blk-crypto-fallback, we should make it just call blk-crypto-fallback directly, so the block devices won't be needed.)
CVE-2026-68137 1 Linux 1 Linux Kernel 2026-08-19 9.8 Critical
In the Linux kernel, the following vulnerability has been resolved: net/x25: fix use-after-free in x25_kill_by_neigh() x25_kill_by_neigh() walks the global X.25 socket list looking for sockets attached to a terminating neighbour. x25_list_lock protects list membership while the lookup is in progress, but it does not pin a socket's lifetime after the lock is dropped. The function currently drops x25_list_lock before calling lock_sock(s). A concurrent close can run x25_release(), remove the same socket from x25_list, and drop the last socket reference in that window. The neighbour teardown path can then lock or inspect a freed struct sock/struct x25_sock. Take sock_hold(s) while x25_list_lock still proves that the list entry is live, then drop the temporary reference after the socket has been locked, rechecked, and released. Recheck x25_sk(s)->neighbour after lock_sock(), because another path may have disconnected the socket before this path acquired the socket lock. Restart the list walk after each disconnect because the list lock was dropped and the previous iterator state may no longer be valid. A QEMU/KASAN run against origin/master reproduced a slab-use-after-free in x25_kill_by_neigh().
CVE-2026-68135 1 Linux 1 Linux Kernel 2026-08-19 5.9 Medium
In the Linux kernel, the following vulnerability has been resolved: net: hip04: fix RX buffer leak on build_skb failure When build_skb() fails in hip04_rx_poll(), the driver jumps to the refill path without releasing the current RX buffer and its DMA mapping. Installing a replacement buffer then overwrites the slot references and leaks both resources. Keep the current slot intact and return budget so NAPI retries the same buffer. Also free a newly allocated RX fragment when dma_map_single() fails. This issue was found by an in-house static analysis tool.
CVE-2026-68124 1 Linux 1 Linux Kernel 2026-08-19 9.6 Critical
In the Linux kernel, the following vulnerability has been resolved: mctp: serial: handle zero-length frames to prevent rx buffer overflow The MCTP serial receive state machine reads a frame length byte in mctp_serial_push_header() case 2 and validates it upper-bound-only: if (c > MCTP_SERIAL_FRAME_MTU) { dev->rxstate = STATE_ERR; } else { dev->rxlen = c; dev->rxpos = 0; dev->rxstate = STATE_DATA; ... } A length of zero passes this check, so rxlen is set to 0 and the state machine advances to STATE_DATA. In mctp_serial_push() STATE_DATA, the incoming byte is stored and rxpos incremented before the terminator is dev->rxbuf[dev->rxpos] = c; dev->rxpos++; dev->rxstate = STATE_DATA; if (dev->rxpos == dev->rxlen) { dev->rxpos = 0; dev->rxstate = STATE_TRAILER; } With rxlen == 0 the "rxpos == rxlen" terminator can never fire (rxpos is already 1 on the first data byte), so subsequent bytes are written past the end of the fixed 74-byte rxbuf, which is the last member of the netdev private area. Every following data byte is an attacker-controlled 1-byte out-of-bounds heap write, and the overflow continues until a frame (0x7e) or escape byte resets the parser -- effectively unbounded. Reaching this requires CAP_NET_ADMIN to attach the N_MCTP line discipline and bring the resulting mctpserialN netdev up, after which the bytes arrive via the tty receive path. Route a zero-length frame straight to STATE_TRAILER instead of STATE_DATA. The trailer/framing bytes are still consumed, and the frame resolves to a zero-length skb that the MCTP core rejects; the parser never enters STATE_DATA with rxlen == 0, so the out-of-bounds write can no longer occur. KASAN, on a frame of 0x7e 0x01 0x00 followed by data bytes (before this change): UBSAN: array-index-out-of-bounds in drivers/net/mctp/mctp-serial.c:370 index 74 is out of range for type 'u8 [74]' BUG: KASAN: slab-out-of-bounds in mctp_serial_tty_receive_buf Write of size 1 at addr ... by task kworker/u16:0 mctp_serial_tty_receive_buf tty_ldisc_receive_buf flush_to_ldisc Allocated by task 152: alloc_netdev_mqs mctp_serial_open v2: route zero-length frames to STATE_TRAILER instead of STATE_ERR so the trailer/framing bytes are still consumed (Jeremy Kerr). Found by 0sec automated security-research tooling (https://0sec.ai).
CVE-2026-64584 1 Linux 1 Linux Kernel 2026-08-19 7.8 High
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_midi: cancel pending IN work before freeing the midi object The f_midi driver embeds a work item (midi->work) whose handler, f_midi_in_work(), dereferences the enclosing struct f_midi through container_of(). This work is armed from two sites: f_midi_complete(), on a normal IN-endpoint completion, and f_midi_in_trigger(), on an ALSA rawmidi output-stream start. Neither f_midi_disable() nor f_midi_unbind() cancels midi->work. f_midi_disable() only disables the endpoints and drains the in_req_fifo; it does not synchronize the work item, and the sound card is released asynchronously to the final free of the midi object. The midi object is reference-counted (midi->free_ref) and is freed in f_midi_free() only once both the usb_function reference and the rawmidi private_data reference have been dropped. In f_midi_unbind(), f_midi_disable() runs before the sound card is released, so while the USB endpoints are already disabled the rawmidi device is still usable by an open substream. A concurrent userspace write on such a substream can reach f_midi_in_trigger() and queue midi->work again after f_midi_disable() has returned. A work item armed this way may still be pending when the last reference drops and f_midi_free() proceeds to kfree(midi), letting f_midi_in_work() dereference the struct after it has been freed, a use-after-free. For this reason cancelling midi->work in f_midi_disable() would not be sufficient: the ALSA trigger path can rearm the work after disable() returns. Cancelling at the refcount-zero free site is the boundary after which neither arming source can survive, because by then both references that keep the midi object alive have been dropped: the USB endpoints are already disabled and the rawmidi device has been released. Fix this by calling cancel_work_sync(&midi->work) in the refcount-zero block of f_midi_free(), before the embedded work_struct is freed along with the rest of the structure. opts->lock is a sleeping mutex, so calling cancel_work_sync() under it is permitted, and the handler takes midi->transmit_lock rather than opts->lock, so no self-deadlock can occur while it waits for a running instance of the work to finish. This issue was found by an in-house static analysis tool.
CVE-2026-64578 1 Linux 1 Linux Kernel 2026-08-19 8.2 High
In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate compound request size before reading StructureSize2 When ksmbd validates a compound (chained) SMB2 request, ksmbd_smb2_check_message() reads pdu->StructureSize2 without first checking that the compound element is large enough to contain it. StructureSize2 is a 2-byte field at offset 64 (__SMB2_HEADER_STRUCTURE_SIZE) from the start of each element. The compound-walking logic only guarantees that a full 64-byte SMB2 header is present for the trailing element: when NextCommand is 0, len is reduced to the number of bytes remaining after next_smb2_rcv_hdr_off. A remote client can craft a compound request whose last element has exactly 64 bytes, so the 2-byte StructureSize2 read at offset 64 extends one byte past the receive buffer, producing a slab-out-of-bounds read. BUG: KASAN: slab-out-of-bounds in ksmbd_smb2_check_message (fs/smb/server/smb2misc.c:402) Read of size 2 at addr ffff888012ae31ac by task kworker/0:1/14 The buggy address is located 172 bytes inside of allocated 173-byte region Workqueue: ksmbd-io handle_ksmbd_work Call Trace: ... kasan_report (mm/kasan/report.c:595) ksmbd_smb2_check_message (fs/smb/server/smb2misc.c:402) handle_ksmbd_work (fs/smb/server/server.c:119) process_one_work (kernel/workqueue.c:3314) worker_thread (kernel/workqueue.c:3397) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) Reject any compound element that is too small to hold StructureSize2 before dereferencing it.
CVE-2026-64577 1 Linux 1 Linux Kernel 2026-08-19 7.5 High
In the Linux kernel, the following vulnerability has been resolved: gtp: check skb_pull_data() return in gtp1u_send_echo_resp() gtp1u_send_echo_resp() ignores skb_pull_data()'s return value. Its caller gtp1u_udp_encap_recv() only guarantees 16 bytes (udphdr + gtp1_header), but the pull requests 20 (gtp1_header_long + udphdr). For a 16-19 byte echo request the pull fails and returns NULL without advancing skb->data; execution continues, and the following skb_push() plus the IP header pushed by iptunnel_xmit() move skb->data below skb->head, tripping skb_under_panic(). Fix it by dropping the packet when skb_pull_data() fails. skbuff: skb_under_panic: ... kernel BUG at net/core/skbuff.c:214! Call Trace: skb_push (net/core/skbuff.c:2648) iptunnel_xmit (net/ipv4/ip_tunnel_core.c:82) gtp_encap_recv (drivers/net/gtp.c:701 drivers/net/gtp.c:808 drivers/net/gtp.c:920) udp_queue_rcv_one_skb (net/ipv4/udp.c:2388) ... Kernel panic - not syncing: Fatal exception in interrupt
CVE-2026-64573 1 Linux 1 Linux Kernel 2026-08-19 7.0 High
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: qca: fix NVM tag length underflow in TLV parser In the TLV_TYPE_NVM branch of qca_tlv_check_data() the tag loop bound is "while (idx < length - sizeof(struct tlv_type_nvm))". "length" is a signed int from the firmware TLV header and sizeof(struct tlv_type_nvm) is a size_t (12), so "length" is converted to size_t and any firmware-supplied "length" < 12 makes the subtraction wrap to a huge value. The loop body then reads a 12-byte struct tlv_type_nvm past the end of the short vmalloc'd firmware buffer (and the EDL_TAG_ID_* handlers can write past it). Rewrite the bound as "idx + sizeof(struct tlv_type_nvm) <= length"; both operands are non-negative, so it no longer underflows and a "length" too small for one record correctly skips the loop. BUG: KASAN: vmalloc-out-of-bounds in qca_download_firmware.isra.0 (drivers/bluetooth/btqca.c:421) Read of size 2 at addr ffffc900000e5004 by task kworker/u9:0/52 Workqueue: hci0 hci_power_on Call Trace: ... kasan_report (mm/kasan/report.c:595) qca_download_firmware.isra.0 (drivers/bluetooth/btqca.c:421 drivers/bluetooth/btqca.c:617) qca_uart_setup (drivers/bluetooth/btqca.c:948) qca_setup (drivers/bluetooth/hci_qca.c:2029) hci_uart_setup (drivers/bluetooth/hci_ldisc.c:438) hci_dev_open_sync (net/bluetooth/hci_sync.c:5227) hci_power_on (net/bluetooth/hci_core.c:920) process_one_work (kernel/workqueue.c:3322) worker_thread (kernel/workqueue.c:3486) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
CVE-2026-64565 1 Linux 1 Linux Kernel 2026-08-19 N/A
In the Linux kernel, the following vulnerability has been resolved: Input: ims-pcu - fix heap-buffer-overflow in ims_pcu_process_data() The `ims_pcu_process_data()` processes incoming URB data byte by byte. However, it fails to check if the `read_pos` index exceeds IMS_PCU_BUF_SIZE. If a malicious USB device sends a packet larger than IMS_PCU_BUF_SIZE, `read_pos` will increment indefinitely. Moreover, since `read_pos` is located immediately after `read_buf`, the attacker can overwrite `read_pos` itself to arbitrarily control the index. This manipulated `read_pos` is subsequently used in `ims_pcu_handle_response()` to copy data into `cmd_buf`, leading to a heap buffer overflow. Specifically, an attacker can overwrite the `cmd_done.wait.head` located at offset 136 relative to `cmd_buf` in the `ims_pcu_handle_response()`. Consequently, when the driver calls `complete(&pcu->cmd_done)`, it triggers a control flow hijack by using the manipulated pointer. Fix this by adding a bounds check for `read_pos` before writing to `read_buf`. If the packet is too long, discard it, log a warning, and reset the parser state. [dtor: factor out resetting packet state, reset checksum as well]
CVE-2026-23394 1 Linux 1 Linux Kernel 2026-08-19 4.7 Medium
In the Linux kernel, the following vulnerability has been resolved: af_unix: Give up GC if MSG_PEEK intervened. Igor Ushakov reported that GC purged the receive queue of an alive socket due to a race with MSG_PEEK with a nice repro. This is the exact same issue previously fixed by commit cbcf01128d0a ("af_unix: fix garbage collect vs MSG_PEEK"). After GC was replaced with the current algorithm, the cited commit removed the locking dance in unix_peek_fds() and reintroduced the same issue. The problem is that MSG_PEEK bumps a file refcount without interacting with GC. Consider an SCC containing sk-A and sk-B, where sk-A is close()d but can be recv()ed via sk-B. The bad thing happens if sk-A is recv()ed with MSG_PEEK from sk-B and sk-B is close()d while GC is checking unix_vertex_dead() for sk-A and sk-B. GC thread User thread --------- ----------- unix_vertex_dead(sk-A) -> true <------. \ `------ recv(sk-B, MSG_PEEK) invalidate !! -> sk-A's file refcount : 1 -> 2 close(sk-B) -> sk-B's file refcount : 2 -> 1 unix_vertex_dead(sk-B) -> true Initially, sk-A's file refcount is 1 by the inflight fd in sk-B recvq. GC thinks sk-A is dead because the file refcount is the same as the number of its inflight fds. However, sk-A's file refcount is bumped silently by MSG_PEEK, which invalidates the previous evaluation. At this moment, sk-B's file refcount is 2; one by the open fd, and one by the inflight fd in sk-A. The subsequent close() releases one refcount by the former. Finally, GC incorrectly concludes that both sk-A and sk-B are dead. One option is to restore the locking dance in unix_peek_fds(), but we can resolve this more elegantly thanks to the new algorithm. The point is that the issue does not occur without the subsequent close() and we actually do not need to synchronise MSG_PEEK with the dead SCC detection. When the issue occurs, close() and GC touch the same file refcount. If GC sees the refcount being decremented by close(), it can just give up garbage-collecting the SCC. Therefore, we only need to signal the race during MSG_PEEK with a proper memory barrier to make it visible to the GC. Let's use seqcount_t to notify GC when MSG_PEEK occurs and let it defer the SCC to the next run. This way no locking is needed on the MSG_PEEK side, and we can avoid imposing a penalty on every MSG_PEEK unnecessarily. Note that we can retry within unix_scc_dead() if MSG_PEEK is detected, but we do not do so to avoid hung task splat from abusive MSG_PEEK calls.
CVE-2025-40307 1 Linux 1 Linux Kernel 2026-08-19 7.8 High
In the Linux kernel, the following vulnerability has been resolved: exfat: validate cluster allocation bits of the allocation bitmap syzbot created an exfat image with cluster bits not set for the allocation bitmap. exfat-fs reads and uses the allocation bitmap without checking this. The problem is that if the start cluster of the allocation bitmap is 6, cluster 6 can be allocated when creating a directory with mkdir. exfat zeros out this cluster in exfat_mkdir, which can delete existing entries. This can reallocate the allocated entries. In addition, the allocation bitmap is also zeroed out, so cluster 6 can be reallocated. This patch adds exfat_test_bitmap_range to validate that clusters used for the allocation bitmap are correctly marked as in-use.