CVE-2026-40873

Severity CVSS v4.0:

HIGH

Type:

CWE-79 Cross-Site Scripting (XSS)

Publication date:

21/04/2026

Last modified:

22/04/2026

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.

Impact

Vector 4.0

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:N CVSS v4.0 Severity and Metrics:

Base Score: 8.90 HIGH
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): Present
Privileges Required (PR): None
User Interaction (UI): Passsive
Confidentiality (VC): High
Integrity (VI): High
Availability (VA): High
Confidentiality (SC): High
Integrity (SI): High
Availability (SA): None

Base Score 4.0

8.90

Severity 4.0

HIGH

CVE-2026-40873

Description

Impact

References to Advisories, Solutions, and Tools