Vulnerability · Published May 22, 2026 · Assigned by Mattermost
CVE-2026-5308Missing request body size limits on Zoom plugin HTTP endpoints
Medium 4.9
In plain English
A medium-severity uncontrolled resource consumption in Mattermost from Mattermost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/mattermost/mattermost-plugin-github | 1.0.1-0.20260410143745-9b41b1fd43c4 | GO-2026-5836 |
| Go | github.com/mattermost/mattermost-plugin-github | 1.0.1-0.20260410143745-9b41b1fd43c4 | GHSA-jmvr-r5hm-fxfr |
| Go | github.com/mattermost/mattermost-server | 11.4.5 | GHSA-jmvr-r5hm-fxfr |
| Go | github.com/mattermost/mattermost-server | 11.6.1 | GHSA-jmvr-r5hm-fxfr |
| Go | github.com/mattermost/mattermost-server | 10.11.15+incompatible, 11.4.5+incompatible, 11.5.4+incompatible, 11.6.1+incompatible | GO-2026-5836 |
| Go | github.com/mattermost/mattermost-server | 10.11.15 | GHSA-jmvr-r5hm-fxfr |
| Go | github.com/mattermost/mattermost-server | 11.5.4 | GHSA-jmvr-r5hm-fxfr |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | 11.6.0 – through 11.6.011.5.0 – through 11.5.311.4.0 – through 11.4.410.11.0 – through 10.11.14 |
Weakness: CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
References
- MMSA-2026-00646 vendor-advisory