CVE-2026-2457: Mattermost allows attackers to spoof permalink embeds

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 sanitize client-supplied post metadata which allows an authenticated attacker to spoof permalink embeds impersonating other users via crafted PUT requests to the post update API endpoint. Mattermost Advisory ID: MMSA-2025-00569

References

github.com/advisories/GHSA-ph22-fw5m-w2q9
github.com/mattermost/mattermost
github.com/mattermost/mattermost/commit/9efe617be8b8f1d036e12721e8e73b69a543ed34
mattermost.com/security-updates
nvd.nist.gov/vuln/detail/CVE-2026-2457

Code Behaviors & Features

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