Is there a public exploit for CVE-2026-66911?

No public exploit for CVE-2026-66911 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-66911?

CVE-2026-66911 scores CVSS 5.3 (v4.0), rated medium.

5.3 Medium

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

CVE-2026-66911

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

Assessment

CVSS: 5.3 (v4.0)
Severity: Medium
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 29 October 2026
Last updated: 29 October 2026
Weakness: CWE-79
Assigner: cvd@cert.pl

CVSS vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

At the source

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