Description
Zimbra is vulnerable to stored cross-site scripting (XSS) via the Content-Location MIME header in email attachments. Due to lack of sanitization of the Content-Location header, an attacker can set it to a javascript: URI. An unauthenticated remote attacker can send a crafted email to a victim; when the victim opens the email in the Zimbra web interface and clicks the attachment name, the JavaScript payload executes in the victim's browser context. This issue was fixed in version 10.1.21
Published: 2026-10-29
Score: 5.3 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Thu, 29 Oct 2026 15:30:00 +0000

Type Values Removed Values Added
Description Zimbra is vulnerable to stored cross-site scripting (XSS) via the Content-Location MIME header in email attachments. Due to lack of sanitization of the Content-Location header, an attacker can set it to a javascript: URI. An unauthenticated remote attacker can send a crafted email to a victim; when the victim opens the email in the Zimbra web interface and clicks the attachment name, the JavaScript payload executes in the victim's browser context. This issue was fixed in version 10.1.21
Title Stored Cross-Site Scripting in Zimbra
First Time appeared Synacor
Synacor zimbra Collaboration
Weaknesses CWE-79
CPEs cpe:2.3:a:synacor:zimbra_collaboration:*:*:*:*:*:*:*:*
Vendors & Products Synacor
Synacor zimbra Collaboration
References
Metrics cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N'}

Subscriptions

Synacor Zimbra Collaboration
cve-icon MITRE

Status: PUBLISHED

Assigner: CERT-PL

Published:

Updated: 2026-10-29T15:22:19.086Z

Reserved: 2026-07-28T12:14:18.398Z

Link: CVE-2026-66911

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-29T16:18:15.390

Modified: 2026-10-29T16:29:56.553

Link: CVE-2026-66911

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-79

    Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')