CVE-2025-27936: Mattermost vulnerable to Observable Timing Discrepancy

April 16, 2025 (updated April 23, 2025)

Mattermost Plugin MSTeams versions <2.1.0 and Mattermost Server versions 10.5.x <=10.5.1 with the MS Teams plugin enabled fail to perform constant time comparison on a MSTeams plugin webhook secret which allows an attacker to retrieve the webhook secret of the MSTeams plugin via a timing attack during webhook secret comparison.

References

github.com/advisories/GHSA-2j87-p623-8cc2
github.com/mattermost/mattermost
mattermost.com/security-updates
nvd.nist.gov/vuln/detail/CVE-2025-27936
pkg.go.dev/vuln/GO-2025-3618

Code Behaviors & Features

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