CVE-2025-13821 — Sensitive Information Exposure in Mattermost Mattermost-server

CWE-200 — Sensitive Information Exposure6 documents5 sources
Severity
5.7MEDIUMNVD
EPSS
0.0%
top 88.77%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
4
Github.com Mattermost Mattermost-serverGithub.com Mattermost Mattermost Server V8Mattermost Server+1 more
Timeline
PublishedFeb 16
Latest updateFeb 23

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

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:NExploitability: 2.1 | Impact: 3.6

Affected Packages4 packages

▶NVDmattermost/mattermost_server10.11.0 — 10.11.10+2
▶Gogithub.com/mattermost_mattermost-server< 5.3.2-0.20251210191531-cd17b61de41b+6
▶Gogithub.com/mattermost_mattermost_server_v8< 8.0.0-20251210191531-cd17b61de41b
▶CVEListV5mattermost/mattermost11.1.0 — 11.1.2+2

🔴Vulnerability Details

4
OSV
Mattermost fails to sanitize sensitive data in WebSocket messages in github.com/mattermost/mattermost-server↗2026-02-23
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GHSA
Mattermost fails to sanitize sensitive data in WebSocket messages↗2026-02-16
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OSV
Mattermost fails to sanitize sensitive data in WebSocket messages↗2026-02-16
▶
CVEList
User profile update exposes password hash and MFA secrets↗2026-02-16
▶

🕵️Threat Intelligence

1
Wiz
CVE-2025-13821 Impact, Exploitability, and Mitigation Steps | Wiz↗
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CVE-2025-13821 — Sensitive Information Exposure | cvebase