GHSA-rmvv-8v8w-rf7x

ghsaUSosv

Mattermost doesn't validate user-supplied input in API request handlers

view advisory published 2026-05-26Licence: CC-BY-4.0

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

describes (1)

Related CVEs.

ID	severity	EPSS	exploitable	published
CVE-2026-4646US	—	0.25% (16th)	—	2026-05-22
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 authentic…

references

External citations — patches, advisories, analysis.

https://github.com/mattermost/mattermostPACKAGE
https://github.com/mattermost/mattermost-plugin-github/commit/c2840e980b3c2bd08db656eaa6a0fe26bcbf4695WEB
https://mattermost.com/security-updatesWEB
https://nvd.nist.gov/vuln/detail/CVE-2026-4646ADVISORY

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