# CVE-2026-3471

## Summary

- **CVE ID:** CVE-2026-3471
- **Severity:** MEDIUM
- **CVSS Score:** 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)
- **CWE:** CWE-939
- **Published:** May 18, 2026
- **Last Modified:** May 18, 2026

## Description

Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent an invalid URL from loading in a pop-up window in the Mattermost Desktop App which allows a malicious server owner to repeated crash the application via calling {{window.open('javascript:alert()');}}. Mattermost Advisory ID: MMSA-2026-00618

## Affected Products

- Mattermost — Mattermost (0)
- Mattermost — Mattermost (6.2.0)
- Mattermost — Mattermost (6.1.1.0)
- Mattermost — Mattermost (5.13.5.0)

## References

- [CNA](https://mattermost.com/security-updates)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.18%
- **EPSS Percentile:** 8.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-12._