CVE-2026-66911

UNKNOWN 0.0

Stored Cross-Site Scripting in Zimbra

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

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

CWE	CWE-79
Vendor	synacor
Product	zimbra collaboration
Published	Oct 29, 2026

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Affected Versions

Synacor / Zimbra Collaboration

0 < 10.1.21

References

NVD ↗ CVE.org ↗ EPSS Data ↗

cert.pl: https://cert.pl/en/posts/2026/10/CVE-2026-66911 wiki.zimbra.com: https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories

Credits

Suraj Disoja (TrustFoundry) Mateusz Borkowski (CERT.PL)