CVE-2026-40872CWE-79CWE-80

mailcow: dockerized vulnerable to stored XSS in autodiscover logs email address field

Critical · published April 21, 2026

CVSS v4.0
9.3
EPSS
0%
Percentile
37.5
In the wild
Unconfirmed
What it is

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the admin dashboard's Autodiscover logs render the EMailAddress value (logged as the "user" field) without HTML escaping. By submitting an unauthenticated Autodiscover request with a crafted EMailAddress containing HTML/JS, the payload is stored in Redis and executed when an admin views the Autodiscover logs. Version 2026-03b fixes the vulnerability.

The record
Technical detail
CVSS v4.0
9.3 · CRITICAL
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:N
EPSS
0.00444 · 37.5th percentile
Weaknesses
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'); CWE-80 · Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
Published
2026-04-21T19:14Z
EPSS history
Timeline
  • 21 APR 19:14Z
    mailcow: dockerized vulnerable to stored XSS in autodiscover logs email address field
    cvelistv5