CVE-2026-4646
Insufficient input validation in GitHub plugin API causes denial of service
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
INFO
Published Date :
May 22, 2026, 10:25 a.m.
Last Modified :
May 22, 2026, 10:25 a.m.
Remotely Exploit :
Yes !
Source :
Mattermost
Affected Products
The following products are affected by CVE-2026-4646
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 9302f53e-dde5-4bf3-b2f2-a83f91ac0eee |
Solution
- Update Mattermost to a version later than 11.6.0.
- Update Mattermost to a version later than 11.5.3.
- Update Mattermost to a version later than 11.4.4.
- Update Mattermost to a version later than 10.11.14.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-4646 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-4646 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
May. 22, 2026
Action Type Old Value New Value Added 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 Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-1287 Added Reference https://mattermost.com/security-updates