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CVE-2026-66911 - Zimbra is vulnerable to stored cross-site scripting (XSS) via the Content-Location MIME header in email attachments. Due

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
INFORMATIONAL
Severity & confidence
Source severityinformational
Platform severityinformational
Confidencehigh
Exploitationunknown
CVSS-
Affected
Reporting sources (1)
NIST NVD - National Vulnerability Database
Open source ↗
Timeline & provenance
Published2026-10-29T16:18:15
Last updated2026-11-01T16:14:23
Ingested2026-10-31T18:18:03
FreshnessNEAR-REAL-TIME
Threat typevulnerability
Recommended action
No recommended action published with this item - review the original source.
Next steps
  1. Identify affected systems in your environment.
  2. Apply the vendor patch or mitigation guidance.
  3. Review logs for indicators described in the advisory.
  4. Follow the affected vendor/product to track updates.
Confidence explanation
Reported by a government or cert-grade source (CISA, NCSC, NVD, ENISA, MSRC).
Source type: standards · Original: NIST NVD - National Vulnerability Database