CVE-2026-66911

MEDIUM
MEDIUM Priority: 0.00 BB Relevance: 61/100
Published: 2026-10-29 Modified: 2026-10-29 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Auth

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: Passive
S: X
AT: None
VC: None
VI: None
VA: None

Description

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

Affected Software (1)

VendorProductVersion
Synacor Zimbra Collaboration 0 < 10.1.21

Bug Bounty Relevance

61 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity

CVSS Score

5.3 / 10.0 v4.0
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/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

EPSS — Exploitation Probability

No EPSS data available

Intelligence Sources

mitre ref →
nvd ref →