CVE-2025-27936 json
Webhook Secret Exposure via Timing attack in MSteams plugin
published 2025-04-16 18 mo ago modified 2026-09-10 1 mo ago also GHSA-2j87-p623-8cc2 , GO-2025-3618 , EUVD-2025-11359
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 28%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- go github.com/mattermost/mattermost/server/v8 8.0.0-20250218121836-2b5275d87136, 8.0.0-20250314142426-c049748b8863, 10.5.2
- go github.com/mattermost/mattermost-plugin-msteams 2.1.0
- go github.com/mattermost/mattermost-server 10.5.2+incompatible
- Mattermost Mattermost 10.5.2, 10.6.0
- govulncheck-vulndb openSUSE Tumbleweed 0.0.20250422T181640-1.1
opensuse advisories openSUSE-SU-2025:15017-1
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 18 mo ago
Exploit prediction
0.34% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N |
| NVD | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
| GitHub | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/mattermost/mattermost/server/v8 | >=10.5.0, <10.5.2 <8.0.0-20250314142426-c049748b8863 <8.0.0-20250218121836-2b5275d87136 |
10.5.2 8.0.0-20250314142426-c049748b8863 8.0.0-20250218121836-2b5275d87136 |
| go | github.com/mattermost/mattermost-plugin-msteams | <2.1.0 all versions |
2.1.0 |
| go | github.com/mattermost/mattermost-server | >=10.5.0+incompatible, <10.5.2+incompatible |
10.5.2+incompatible |
| go | github.com/mattermost/mattermost-server/v5 | all versions |
no fix listed |
| go | github.com/mattermost/mattermost-server/v6 | all versions |
no fix listed |
Affected products
- Mattermost Mattermost
Classification
- Weakness
-
- CWE-208 Observable Timing Discrepancy
References
-
mattermost.com
/security-updates
web, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2025-27936
advisory
-
github.com
/mattermost/mattermost
package
-
pkg.go.dev
/vuln/GO-2025-3618
web
-
github.com
/advisories/GHSA-2j87-p623-8cc2
advisory
Sources
- CVE List CVE-2025-27936
- GitHub Advisory GHSA-2j87-p623-8cc2
- NVD CVE-2025-27936
- OSV GO-2025-3618
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.