# CVE-2026-13426: Client4 fails to validate path parameters

> CVE-2026-13426: Client4 fails to validate path parameters. CVSS 5.4 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-13426
Last updated: 2026-06-26T16:12:55Z

- Published: 2026-06-26 13:47 UTC · Updated: 2026-06-26 16:12 UTC · Assigner: Mattermost
- CVSS: 5.4 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
- EPSS: 0.29%, 21th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-22

## Description

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 crafted IDs containing path traversal components. Mattermost Advisory ID: MMSA-2025-00532

## Affected vendors and products

- Mattermost: github.com/mattermost/mattermost/server/public

## Tracked companies

- [Mattermost](https://rewindex.com/company/mattermost.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-13426)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-13426)
- [https://mattermost.com/security-updates](https://mattermost.com/security-updates)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-13426 · Markdown: https://rewindex.com/cve/CVE-2026-13426.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-13426 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:15:30.918Z