Mattermost fails to validate user permissions in Boards
Mattermost versions 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to validate the user permission when accessing the files and subscribing to the block in Boards, which allows an authenticated user to access other board files and was able to subscribe to the block from other boards that the user does not have access to
This issue can be reached over the network, attack complexity is high, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity none, availability none.
The score comes from this vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
CVE-2025-13870 is classified as CWE-284: Improper Access Control. The software does not restrict an action to the actors that should be allowed to perform it.
CVE-2025-13870 is recorded against 6 packages.
Published on 2 December 2025 and last revised on 3 March 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.
nvd.nist.gov (Advisory)
github.com (Web)
github.com (Package)
mattermost.com (Web)
github.com/mattermost/mattermost has other advisories on record. If you are patching this one, these are worth checking on the same host:
These advisories are the same class of weakness (CWE-284: Improper Access Control) in other software:
Details
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| github.com/mattermost/mattermost | — | — |
| github.com/mattermost/mattermost-server | — | — |
| github.com/mattermost/mattermost-server/v5 | — | — |
| github.com/mattermost/mattermost-server/v6 | — | — |
| github.com/mattermost/mattermost/server/v8 | — | — |
| mattermost-server | 10.11.0 | 10.11.5 |
References
Similar Threats
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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.
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