CVE-2025-27936
Webhook Secret Exposure via Timing attack in MSteams plugin
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Webhook Secret Exposure via Timing attack in MSteams plugin
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.
- Record
CVE-2025-27936- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-208
- Updated
- 2026-11-02
EUVDEUVD-2025-11359
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.
- Record
EUVD-2025-11359- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-2j87-p623-8cc2
Mattermost vulnerable to Observable Timing Discrepancy
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.
- Record
GHSA-2j87-p623-8cc2- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-208
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2025-27936- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N - CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-208
- Updated
- 2026-11-02
OSV
Webhook Secret Exposure via Timing attack in MSteams plugin
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.
- Record
CVE-2025-27936- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-208
- Updated
- 2026-11-02
OSVGHSA-2j87-p623-8cc2
Mattermost vulnerable to Observable Timing Discrepancy
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.
- Record
GHSA-2j87-p623-8cc2- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-208
- Updated
- 2026-11-02
OSVGO-2025-3618 No score
Mattermost vulnerable to Observable Timing Discrepancy in github.com/mattermost/mattermost-plugin-msteams
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.
- Record
GO-2025-3618- Updated
- 2026-11-02
OSVopenSUSE-SU-2025:15017-1 No score
govulncheck-vulndb-0.0.20250422T181640-1.1 on GA media
These are all security issues fixed in the govulncheck-vulndb-0.0.20250422T181640-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2025:15017-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/mattermost/mattermost/server/v8Go |
10.5.0 up to 10.5.2 | 10.5.2 |
github.com/mattermost/mattermost-plugin-msteamsGo |
through 1.15.0 | 2.1.0 |
github.com/mattermost/mattermost/server/v8Go |
before 8.0.0-20250314142426-c049748b8863 | 8.0.0-20250314142426-c049748b8863 |
github.com/mattermost/mattermost-plugin-msteamsGo |
before 2.1.0 | 2.1.0 |
github.com/mattermost/mattermost-plugin-msteamsGo |
All versions | None known |
github.com/mattermost/mattermost-serverGo |
10.5.0+incompatible up to 10.5.2+incompatible | 10.5.2+incompatible |
github.com/mattermost/mattermost-server/v5Go |
All versions | None known |
github.com/mattermost/mattermost-server/v6Go |
All versions | None known |
github.com/mattermost/mattermost/server/v8Go |
before 8.0.0-20250218121836-2b5275d87136 | 8.0.0-20250218121836-2b5275d87136 |
govulncheck-vulndbopenSUSE:Tumbleweed From an advisory covering 23 CVEs |
before 0.0.20250422T181640-1.1 | 0.0.20250422T181640-1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-27936 is a medium vulnerability (CVSS 5.3) in Mattermost, published April 16, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.34%, the 28th percentile. Fixed in github.com/mattermost/mattermost/server/v8 10.5.2.
References
mattermost.com/security-updates
nvd.nist.gov/vuln/detail/CVE-2025-27936
pkg.go.dev/vuln/GO-2025-3618
github.com/advisories/GHSA-2j87-p623-8cc2
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lists.opensuse.org/archives/list/[email protected]/thread/XCF7AZBKQYAQXK32J6F54H6NREFBK2V7
suse.com/security/cve/CVE-2019-15119