Medium severity · published Jul 18, 2025
CVE-2025-6226
IDOR in CreatePost API allows for timeboxed message disclosure
6.5
CVSS
0.4%
EPSS
No
On KEV
Description
Mattermost versions 10.5.x <= 10.5.6, 10.8.x <= 10.8.1, 10.7.x <= 10.7.3, 9.11.x <= 9.11.16 fail to verify authorization when retrieving cached posts by PendingPostID which allows an authenticated user to read posts in private channels they don't have access to via guessing the PendingPostID of recently created posts.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 31% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
Mattermost · Mattermost
10.5.0 through 10.5.6; 10.8.0 through 10.8.1; 10.7.0 through 10.7.3; 9.11.0 through 9.11.16 · source: vendor
MS
Mattermost Server · Mattermost
9.11.0 before 9.11.17; 10.5.0 before 10.5.7; 10.7.0 before 10.7.4; 10.8.0 before 10.8.2 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-6226
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-6226
Vendor Advisory
https://mattermost.com/security-updates
More from Mattermost
9.9
CVE-2026-4858
Path traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.
9.9
CVE-2025-12421
Account Takeover via Code Exchange Endpoint
9.9
CVE-2025-12419
Account takeover on OAuth/OpenID-enabled servers
9.9
CVE-2025-4981
Path Traversal Leading to RCE by Any Authenticated Mattermost User
9.8
CVE-2023-6458
Client side path traversal due to lack of route parameters validation