Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to rate limit login requests which allows unauthenticated remote attackers to cause denial of service (server crash and restart) via HTTP/2 single packet attack with 100+ parallel login requests.. Mattermost Advisory ID: MMSA-2025-00566
Project Subscriptions
No data.
Advisories
No advisories yet.
Fixes
Solution
Update Mattermost to versions 11.5.0, 11.4.1, 11.3.2, 11.2.4, 10.11.12 or higher.
Workaround
No workaround given by the vendor.
References
| Link | Providers |
|---|---|
| https://mattermost.com/security-updates |
|
History
Wed, 25 Mar 2026 16:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to rate limit login requests which allows unauthenticated remote attackers to cause denial of service (server crash and restart) via HTTP/2 single packet attack with 100+ parallel login requests.. Mattermost Advisory ID: MMSA-2025-00566 | |
| Title | Denial of Service via HTTP/2 single packet attack on login endpoint | |
| Weaknesses | CWE-400 | |
| References |
| |
| Metrics |
cvssV3_1
|
Projects
Sign in to view the affected projects.
Status: PUBLISHED
Assigner: Mattermost
Published:
Updated: 2026-03-25T16:24:47.694Z
Reserved: 2026-02-23T22:18:41.232Z
Link: CVE-2026-26233
No data.
Status : Received
Published: 2026-03-25T17:16:53.143
Modified: 2026-03-25T17:16:53.143
Link: CVE-2026-26233
No data.
OpenCVE Enrichment
No data.
Weaknesses