How severe is CVE-2025-27936?

CVE-2025-27936 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2025-27936 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-27936?

CVE-2025-27936 primarily affects Mattermost Mattermost Server. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-27936?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-27936 have an EU (EUVD) identifier?

Yes. CVE-2025-27936 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-11359.

When was CVE-2025-27936 published?

CVE-2025-27936 was published on 2025-04-16 and last updated on 2026-06-17.

CVE-2025-27936

CVE-2025-27936 is a medium-severity vulnerability in Mattermost Mattermost Server with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-208.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (21st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-11359
Weakness: CWE-208
Affected product: Mattermost Mattermost Server
Published: 2025-04-16
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2025-27936?: 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.
How severe is CVE-2025-27936?: CVE-2025-27936 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2025-27936 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-27936?: CVE-2025-27936 primarily affects Mattermost Mattermost Server. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-27936?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-27936 have an EU (EUVD) identifier?: Yes. CVE-2025-27936 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-11359.
When was CVE-2025-27936 published?: CVE-2025-27936 was published on 2025-04-16 and last updated on 2026-06-17.

References

https://mattermost.com/security-updates

Affected products (2)

cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
cpe:2.3:a:mattermost:ms_teams:*:*:*:*:*:*:*:*

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