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CVE-2026-26233 Moderate

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.

Exploit probability 0.3%
Published April 2, 2026
Required by Not available
Last source change April 2, 2026

02 / AFFECTED SOFTWARE

Affected packages

Unknown Unknown

43 explicit affected versions

Go github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server

03 / CONNECTIONS

Connected vulnerabilities

related OPENSUSE-SU-2026:21483-1

04 / EVIDENCE

Source records

Open Source Vulnerabilities GHSA-247x-7qw8-fp98

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

View original source
Open Source Vulnerabilities GO-2026-4916

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.

View original source
Open Source Vulnerabilities CVE-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 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

View original source

05 / REFERENCES

Further evidence