PT-2026-1290 · Zimbra · Zimbra Collaboration

Published 2026-01-05 · Updated 2026-03-19 · CVE-2025-66376

Positive Technologies · (AI Summary)

CVSS v3.1

7.2

High

AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Name of the Vulnerable Software and Affected Versions Zimbra Collaboration (ZCS) versions prior to 10.0.18 Zimbra Collaboration (ZCS) versions prior to 10.1.13

Description The software contains a stored cross-site scripting (XSS) issue within the Classic UI. This occurs due to Cascading Style Sheets (CSS) @import directives in an HTML email message. The issue allows for malicious code execution when a user views a crafted email.

Recommendations Update to Zimbra Collaboration (ZCS) version 10.0.18 or later. Update to Zimbra Collaboration (ZCS) version 10.1.13 or later.

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

BDU:2026-01010

CVE-2025-66376

Affected Products

Zimbra Collaboration

References · 26

• https://wiki.zimbra.com/wiki/Security_Center · Vendor Advisory
• https://bdu.fstec.ru/vul/2026-01010 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2025-66376 · Security Note
• https://cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-66376 · Note
• https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.13#Security_Fixes · Note
• https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy · Note
• https://twitter.com/ThreatSynop/status/2034454750377246941 · Twitter Post
• https://t.me/CVEtracker/41385 · Telegram Post
• https://twitter.com/VivekIntel/status/2034114447661556035 · Twitter Post
• https://twitter.com/the_yellow_fall/status/2034464189914247537 · Twitter Post
• https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories · Vendor Advisory, Security Note
• https://twitter.com/VulmonFeeds/status/2008325603968123079 · Twitter Post
• https://twitter.com/NewsNerdie/status/2034540853746692521 · Twitter Post
• https://twitter.com/threatcluster/status/2034578326866591844 · Twitter Post
• https://twitter.com/PrakkiSathwik/status/2034276256083038337 · Twitter Post