CVE-2025-13821

Name: CVE-2025-13821
Creator: NVD / NIST
Published: 2026-02-16T12:16:21.423+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.7/10EPSS 0.20%

Last modified Jun 17, 2026

CVE-2025-13821 is a medium-severity vulnerability rated 5.7/10 on the CVSS scale. Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to sanitize sensitive data in WebSocket messages which allows authenticated users to exfiltrate password hashes and MFA secrets via profile nickname updates or email verification events. Mattermost Advisory ID: MMSA-2025-00560. EPSS estimates a 0.20% chance of exploitation in the next 30 days.

Description

Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to sanitize sensitive data in WebSocket messages which allows authenticated users to exfiltrate password hashes and MFA secrets via profile nickname updates or email verification events. Mattermost Advisory ID: MMSA-2025-00560

Metrics

CVSS 3.1

5.7/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N

EPSS Probability

0.20%

9.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-200

Affected Software

Vendor	Product	Versions
Mattermost	Mattermost Server	>= 10.11.0, < 10.11.10
Mattermost	Mattermost Server	>= 11.1.0, < 11.1.3
Mattermost	Mattermost Server	>= 11.2.0, < 11.2.2

References

https://mattermost.com/security-updatesVendor Advisory

Timeline

Published: Feb 16, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-13821?

How severe is CVE-2025-13821?

CVE-2025-13821 has a CVSS score of 5.7/10 (MEDIUM severity). The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.

How do I fix CVE-2025-13821?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-13821?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST