CVE-2026-4646

Insufficient input validation in GitHub plugin API causes denial of service

State: Published
Severity: 4.3 Medium
Published: May 22, 2026
Updated: May 22, 2026
Reserved: Mar 23, 2026

Description

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate user-supplied input in API request handlers which allows an authenticated attacker to crash the plugin process via a crafted HTTP request to the PR details endpoint.. Mattermost Advisory ID: MMSA-2026-00638

Scores

CVSS	Score	Vector	Source
3.1	4.3 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L	Mattermost

Weaknesses

CWE-1287 Improper Validation of Specified Type of Input

Affected Products

Product	Versions
MattermostMattermost	11.6.0 through 11.6.0Affected 11.5.0 through 11.5.3Affected 11.4.0 through 11.4.4Affected 10.11.0 through 10.11.14Affected 11.7.0Not affected 11.6.1Not affected 11.5.4Not affected 11.4.5Not affected 10.11.15Not affected

References

MMSA-2026-00638vendor-advisory

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