How severe is CVE-2026-13426?

Medium severity. CVSS v3 base score is 5.4 out of 10.

Path Traversal in Mattermost Github.com/mattermost/mattermost/server/public

Q: What is CVE-2026-13426?

CVE-2026-13426 is a medium-severity vulnerability in Mattermost Github.com/mattermost/mattermost/server/public, classified under Path Traversal. CVSS score: 5.4/10. Published 2026-06-26.

CVE-2026-13426

The Mattermost Go module github.com/mattermost/mattermost/server/public versions < v0.1.22 fail to validate path parameters when constructing API route paths which allows an attacker to redirect API calls to unintended endpoints via crafte…

Vulnerability class: Path Traversal (Directory Traversal)

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N.

Affected products

Mattermost Github.com/mattermost/mattermost/server/public — versions v0.0.0, v0.1.22

Weakness classification (CWE)

CWE-22 — Path Traversal

References

responsibledisclosure@mattermost.com (vendor-advisory)

Frequently asked questions

What is CVE-2026-13426?: CVE-2026-13426 is a medium-severity vulnerability in Mattermost Github.com/mattermost/mattermost/server/public, classified under Path Traversal. CVSS score: 5.4/10. Published 2026-06-26.
How severe is CVE-2026-13426?: Medium severity. CVSS v3 base score is 5.4 out of 10.