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Vulnerability · Published Feb 16, 2026 · Assigned by Mattermost

CVE-2025-14350Information disclosure via channel mentions in posts

Medium 4.3

In plain English

A medium-severity missing authorization in Mattermost from Mattermost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.2%top 91.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate team membership when processing channel mentions which allows authenticated users to determine the existence of teams and their URL names via posting channel shortlinks and observing the channel_mentions property in the API response. Mattermost Advisory ID: MMSA-2025-00563

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/mattermost/mattermost-serverno fix listedGO-2026-4521
Gogithub.com/mattermost/mattermost-serverno fix listedGHSA-57cc-2pf4-mhmx
Gogithub.com/mattermost/mattermost-serverno fix listedGHSA-57cc-2pf4-mhmx
Gogithub.com/mattermost/mattermost-serverno fix listedGHSA-57cc-2pf4-mhmx
Gogithub.com/mattermost/mattermost-server5.3.2-0.20251209134645-761e56bb11ccGHSA-57cc-2pf4-mhmx
Gogithub.com/mattermost/mattermost-serverno fix listedGO-2026-4521
Gogithub.com/mattermost/mattermost-serverno fix listedGO-2026-4521
Gogithub.com/mattermost/mattermost-serverno fix listedGO-2026-4521
Gogithub.com/mattermost/mattermost-server/v5no fix listedGO-2026-4521
Gogithub.com/mattermost/mattermost-server/v6no fix listedGO-2026-4521
Gogithub.com/mattermost/mattermost/server/v88.0.0-20251209134645-761e56bb11ccGO-2026-4521
Gogithub.com/mattermost/mattermost/server/v88.0.0-20251209134645-761e56bb11ccGHSA-57cc-2pf4-mhmx

Affected products (as reported)

VendorProductVersions
Mattermost Mattermost 11.1.0 – through 11.1.210.11.0 – through 10.11.911.2.0 – through 11.2.1

Weakness: CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

References