CVE-2026-26233
published 2026-03-25CVE-2026-26233: 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…
PriorityP335medium6.5CVSS 3.1
AVNACLPRLUINSUCNINAH
EPSS
0.30%
22.8th percentile
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
Affected
16 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| github.com | mattermost_mattermost-server | >= 10.11.0-rc1 < 10.11.12 | 10.11.12 |
| github.com | mattermost_mattermost-server | >= 10.11.0-rc1+incompatible < 10.11.12+incompatible | 10.11.12+incompatible |
| github.com | mattermost_mattermost-server | >= 11.2.0-rc1 < 11.2.4 | 11.2.4 |
| github.com | mattermost_mattermost-server | >= 11.2.0-rc1+incompatible < 11.2.4+incompatible | 11.2.4+incompatible |
| github.com | mattermost_mattermost-server | >= 11.3.0-rc1 < 11.3.2 | 11.3.2 |
| github.com | mattermost_mattermost-server | >= 11.3.0-rc1+incompatible < 11.3.2+incompatible | 11.3.2+incompatible |
| github.com | mattermost_mattermost-server | >= 11.4.0-rc1 < 11.4.1 | 11.4.1 |
| github.com | mattermost_mattermost-server | >= 11.4.0-rc1+incompatible < 11.4.1+incompatible | 11.4.1+incompatible |
| mattermost | mattermost | 10.11.0 – 10.11.11 | — |
| mattermost | mattermost | 11.2.0 – 11.2.3 | — |
| mattermost | mattermost | 11.3.0 – 11.3.1 | — |
| mattermost | mattermost | 11.4.0 – 11.4.0 | — |
| mattermost | mattermost_server | >= 10.11.0 < 10.11.12 | 10.11.12 |
| mattermost | mattermost_server | >= 11.2.0 < 11.2.4 | 11.2.4 |
| mattermost | mattermost_server | >= 11.3.0 < 11.3.2 | 11.3.2 |
| mattermost | mattermost_server | >= 11.4.0 < 11.4.1 | 11.4.1 |
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OSV
Mattermost doesn't rate limit login requests, allowing DoS in github.com/mattermost/mattermost-server
osv·2026-04-02
CVE-2026-26233 Mattermost doesn't rate limit login requests, allowing DoS in github.com/mattermost/mattermost-server
Mattermost doesn't rate limit login requests, allowing DoS in github.com/mattermost/mattermost-server
Mattermost doesn't rate limit login requests, allowing DoS in github.com/mattermost/mattermost-server.
NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.
(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)
The additional affected modules and versions are: github.com/mattermost/mattermost-server from v8.0.0-20260105080200-d27a2195068d before v8.0.0-20260217110922-b7d4a1f1f59b.
GHSA
Mattermost doesn't rate limit login requests, allowing DoS
ghsa·2026-03-25
CVE-2026-26233 [MEDIUM] CWE-400 Mattermost doesn't rate limit login requests, allowing DoS
Mattermost doesn't rate limit login requests, allowing DoS
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
OSV
Mattermost doesn't rate limit login requests, allowing DoS
osv·2026-03-25
CVE-2026-26233 [MEDIUM] Mattermost doesn't rate limit login requests, allowing DoS
Mattermost doesn't rate limit login requests, allowing DoS
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
No detection rules found.
No public exploits indexed.
2026-03-25
Published