CVE-2026-7521: SAML certificate deletion allows path traversal to delete arbitrary files outside the config directory

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-28 · updated 2026-07-29
Weakness: CWE-22

Description

Mattermost versions 11.8.x <= 11.8.0, 11.7.x <= 11.7.3, 11.6.x <= 11.6.5, 10.11.x <= 10.11.20 fail to verify file deletion path which allows an admin with SAML system-console write permissions to delete arbitrary files outside the config directory from the server via the remove file endpoint.. Mattermost Advisory ID: MMSA-2026-00666

Affected products

Mattermost: from 10.11.0 before 10.11.21; from 11.6.0 before 11.6.6; from 11.7.0 before 11.7.4; from 11.8.0 before 11.8.1 — fixed in 10.11.21, 11.6.6, 11.7.4, 11.8.1

How to fix

Upgrade to a fixed version: Mattermost 10.11.21, 11.6.6, 11.7.4, 11.8.1. Check the vendor advisory for mitigations.

References

https://mattermost.com/security-updates

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