CVE-2026-24458: Mattermost fails to properly handle very long passwords

March 16, 2026 (updated March 17, 2026)

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly handle very long passwords, which allows an attacker to overload the server CPU and memory via executing login attempts with multi-megabyte passwords. Mattermost Advisory ID: MMSA-2026-00587

References

github.com/advisories/GHSA-m5rv-56xx-hfc6
github.com/mattermost/mattermost
github.com/mattermost/mattermost/commit/7201f42d955f1bc44719b862132546626b60a180
mattermost.com/security-updates
nvd.nist.gov/vuln/detail/CVE-2026-24458

Code Behaviors & Features

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