CVE-2025-27936

Webhook Secret Exposure via Timing attack in MSteams plugin

CVSS 3.1 5.3 MEDIUMEUVD CVSS 3.1 5.3 CVSS 3.1 · [email protected] · Secondary 5.3 MEDIUMCVSS 3.1 · [email protected] · Primary 5.9 MEDIUMCVSS_V3 Publisher rating MODERATEFixed by github.com/mattermost/mattermost/server/v8 10.5.2 Fixed by github.com/mattermost/mattermost/server/v8 8.0.0-20250314142426-c049748b8863 Fixed by github.com/mattermost/mattermost-plugin-msteams 2.1.0osv · severity unknownFixed by github.com/mattermost/mattermost-server 10.5.2+incompatible Fixed by github.com/mattermost/mattermost/server/v8 8.0.0-20250218121836-2b5275d87136KEV status unknown

Original advisory

cve-program · CVE-2025-27936

Published

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.

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euvd · EUVD-2025-11359

Published

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nvd · CVE-2025-27936

Published

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osv · GHSA-2j87-p623-8cc2

Published

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osv · GO-2025-3618

Published

Mattermost vulnerable to Observable Timing Discrepancy in github.com/mattermost/mattermost-plugin-msteams. 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-plugin-msteams before v2.1.0.

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Affected versions, risk and source history

Exploitation and risk

Source status

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Risk history

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Advisory history

14 saved versions

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15 Nov 2026 03:39:55 UTC