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SSTI in Quota and Quarantine Notification Template

Critical
FreddleSpl0it published GHSA-8p7g-6cjj-wr9m Jul 17, 2025

Package

mailcow: dockerized

Affected versions

< 2025-07

Patched versions

>= 2025-07

Description

Impact

A Server-Side Template Injection (SSTI) vulnerability exists in the notification template system used by mailcow for sending quota and quarantine alerts. The template rendering engine allows template expressions that may be abused to execute code in certain contexts.

The issue requires admin-level access to mailcow UI to configure templates, which are automatically rendered during normal system operation.

Patches

Stable: 2025-07
Legacy: 8c5f6c0

Credits

Natalia Baranova from Selectel

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

CVE ID

CVE-2025-53909

Weaknesses

No CWEs