CVE-2026-21388
LOW3.7EPSS 0.02%Mattermost MS Teams plugin doesn't limit the request body size on the /lifecycle webhook endpoint
Published: 4/9/2026Modified: 5/5/2026
Also known as:GHSA-x274-8qfc-hrgf
Description
Mattermost Plugins versions <=2.3.1 fail to limit the request body size on the {{/lifecycle}} webhook endpoint which allows an authenticated attacker to cause memory exhaustion and denial of service via sending an oversized JSON payload. Mattermost Advisory ID: MMSA-2026-00610.
Affected packages (1)
- Go/github.com/mattermost/mattermost-plugin-msteamsfrom 0, < 1.15.1-0.20260213190728-6fe4d295592e
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | LOW3.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L |
References (5)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-21388
- PATCHhttps://github.com/mattermost/mattermost-plugin-msteams
- WEBhttps://github.com/mattermost/mattermost-plugin-msteams/commit/6fe4d295592ecc8767d67e69286cbeec01be3210
- WEBhttps://github.com/mattermost/mattermost-plugin-msteams/releases/tag/v2.3.2
- WEBhttps://mattermost.com/security-updates