4.9
MEDIUM CVSS 3.1
CVE-2026-5308
Missing request body size limits on Zoom plugin HTTP endpoints
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 enforce request body size limits on plugin HTTP endpoints which allows an attacker to cause a denial of service via crafted oversized HTTP requests.. Mattermost Advisory ID: MMSA-2026-00646

INFO

Published Date :

May 22, 2026, 10:20 a.m.

Last Modified :

May 22, 2026, 10:20 a.m.

Remotely Exploit :

Yes !

Source :

Mattermost
Affected Products

The following products are affected by CVE-2026-5308 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
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM 9302f53e-dde5-4bf3-b2f2-a83f91ac0eee
Solution
Update Mattermost to a fixed version to prevent DoS from oversized HTTP requests.
  • Update Mattermost to version 11.6.1 or later.
  • Update Mattermost to version 11.5.4 or later.
  • Update Mattermost to version 11.4.5 or later.
  • Apply recommended security patches promptly.

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-2026-5308 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-5308 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 enforce request body size limits on plugin HTTP endpoints which allows an attacker to cause a denial of service via crafted oversized HTTP requests.. Mattermost Advisory ID: MMSA-2026-00646
    Added CVSS V3.1 AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
    Added CWE CWE-400
    Added Reference https://mattermost.com/security-updates
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.