CVE-2026-40873 | THREATINT

Description

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the Quarantine details modal injects attachment filenames into HTML without escaping, allowing arbitrary HTML/JS execution. An attacker can deliver an email with a crafted attachment name so that when an admin views the quarantine item, JavaScript executes in their browser, taking over their account. Version 2026-03b fixes the vulnerability.

PUBLISHED Reserved 2026-04-15 | Published 2026-04-21 | Updated 2026-04-21 | Assigner GitHub_M

HIGH: 8.9CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:N

Problem types

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)

Product status

< 2026-03b

affected

References

github.com/...erized/security/advisories/GHSA-2xjc-rg88-jvpp exploit

github.com/...erized/security/advisories/GHSA-2xjc-rg88-jvpp

cve.org (CVE-2026-40873)

nvd.nist.gov (CVE-2026-40873)

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