CVE-2026-66912 (GCVE-0-2026-66912)

Vulnerability from cvelistv5 – Published: 2026-10-29 15:22 – Updated: 2026-10-29 15:22
VLAI
Title
Stored Cross-Site Scripting in Zimbra
Summary
Zimbra is vulnerable to Stored Cross-Site Scripting (XSS) via the From email header during HTML reply composition in Classic UI. Due to insufficient sanitization of the From header value, a remote attacker can send a crafted email containing a malicious From header with an embedded JavaScript payload. When the victim opens the message in Classic UI and clicks Reply while composing in HTML mode with reply headers disabled, the unsanitized From header content is rendered as HTML and the JavaScript payload executes in the victim's browser, potentially allowing the attacker to steal session information or perform actions on behalf of the victim. This issue was fixed in version 10.1.21
Severity
5.3 (Medium)
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
CWE
  • CWE-79 - Improper neutralization of input during web page generation ('cross-site scripting')
Assigner
CERT-PL CNA under the ENISA root
CNA scorecard B 81/100 over 256 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Synacor Zimbra Collaboration Affected: 0 , < 10.1.21 (semver)
    cpe:2.3:a:synacor:zimbra_collaboration:*:*:*:*:*:*:*:*
Create a notification for this product.
Credits
Mateusz Borkowski (CERT.PL)
Show details on NVD website
To clipboard 

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}



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