PT-2026-41647 · Mattermost · Mattermost Plugins

Eahmed · CVE-2026-6342 · Published 2026-05-18 · Updated 2026-05-18

Positive Technologies (AI Summary)

CVSS v3.1

4.3

Medium

Base vector

AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Name of the Vulnerable Software and Affected Versions Mattermost Plugins versions prior to 11.5

Description An issue exists where the software fails to appropriately check for valid namespaces. This allows plugin users to create subscriptions to groups that were not whitelisted by creating groups that share the same prefix as a whitelisted group.

Recommendations Update to a version newer than 11.5.

Fix

DoS

Incorrect Authorization

Weakness Enumeration

CWE-863

Related Identifiers

CVE-2026-6342

Affected Products

Mattermost Plugins

References · 5

• https://nvd.nist.gov/vuln/detail/CVE-2026-6342 · Security Note
• https://mattermost.com/security-updates · Vendor Advisory
• https://t.me/CVEtracker/54108 · Telegram Post
• https://twitter.com/CVEarity/status/2056409931084157169 · Twitter Post
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-6342 · Note