CVE-2025-27715

Mattermost versions 9.11.x <= 9.11.8 fail to prompt for explicit approval before adding a team admin to a private channel, which team admins to joining private channels via crafted permalink links without explicit consent from them.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTNIST
3.3 LOW
NETWORK
HIGH
HIGH
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:N
MattermostCNA
3.3 LOW
NETWORK
HIGH
HIGH
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:N
CISA-ADPADP
---
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Base Score
CVSS 3.x
EPSS Score
Percentile: 6%
VendorProductVersion
mattermostmattermost_server
9.11.0 ≤
𝑥
< 9.11.9
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://mattermost.com/security-updates