CVE-2025-6226
IDOR in CreatePost API allows for timeboxed message disclosure
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- 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
IDOR in CreatePost API allows for timeboxed message disclosure
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.
- Record
CVE-2025-6226- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-306
- Updated
- 2026-11-02
EUVDEUVD-2025-21867
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.
- Record
EUVD-2025-21867- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-7h34-9chr-58qh
Mattermost Missing Authentication for Critical Function
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.
- Record
GHSA-7h34-9chr-58qh- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-306
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2025-6226- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-306
- Updated
- 2026-11-02
OSV
IDOR in CreatePost API allows for timeboxed message disclosure
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.
- Record
CVE-2025-6226- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-306
- Updated
- 2026-11-07
OSVGHSA-7h34-9chr-58qh
Mattermost Missing Authentication for Critical Function
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.
- Record
GHSA-7h34-9chr-58qh- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-306
- Updated
- 2026-11-02
OSVGO-2025-3819 No score
Mattermost Missing Authentication for Critical Function in github.com/mattermost/mattermost-server
Mattermost Missing Authentication for Critical Function in github.com/mattermost/mattermost-server
- Record
GO-2025-3819- Updated
- 2026-11-02
OSVopenSUSE-SU-2025:15405-1 No score
govulncheck-vulndb-0.0.20250730T213748-1.1 on GA media
These are all security issues fixed in the govulncheck-vulndb-0.0.20250730T213748-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2025:15405-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/mattermost/mattermost-serverGo |
10.5.0 up to 10.5.7 | 10.5.7 |
github.com/mattermost/mattermost-serverGo |
10.8.0 up to 10.8.2 | 10.8.2 |
github.com/mattermost/mattermost-serverGo |
10.7.0 up to 10.7.4 | 10.7.4 |
github.com/mattermost/mattermost-serverGo |
9.11.0 up to 9.11.17 | 9.11.17 |
github.com/mattermost/mattermost/server/v8Go |
before 8.0.0-20250520130510-fa40a8c5d47f | 8.0.0-20250520130510-fa40a8c5d47f |
github.com/mattermost/mattermost-serverGo |
9.11.0+incompatible up to 9.11.17+incompatible, 10.5.0+incompatible up to 10.5.7+incompatible, 10.7.0+incompatible up to 10.7.4+incompatible, 10.8.0+incompatible up to 10.8.2+incompatible | 9.11.17+incompatible10.5.7+incompatible10.7.4+incompatible10.8.2+incompatible |
github.com/mattermost/mattermost-server/v5Go |
All versions | None known |
github.com/mattermost/mattermost-server/v6Go |
All versions | None known |
govulncheck-vulndbopenSUSE:Tumbleweed From an advisory covering 56 CVEs |
before 0.0.20250730T213748-1.1 | 0.0.20250730T213748-1.1 |
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-2025-6226 is a medium vulnerability (CVSS 6.5) in Mattermost, published July 18, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.37%, the 31st percentile. Fixed in github.com/mattermost/mattermost-server 10.5.7.
References
mattermost.com/security-updates
nvd.nist.gov/vuln/detail/CVE-2025-6226
github.com/mattermost/mattermost/commit/fa40a8c5d47fed5c166429a1c1bd95d62b241d89
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suse.com/security/cve/CVE-2024-44905