CVE-2024-9155 Insufficient Authorization On Unlinked Channel Files
Attackers can view unlinked channel files in channels they belong to due to insufficient authorization checks in Mattermost.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2024-9155?
CVE-2024-9155 is a medium-severity missing authorization vulnerability in Mattermost Mattermost Server, published on 26 Sep 2024. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Mattermost versions 9.10.x <= 9.10.1, 9.9.x <= 9.9.2, 9.5.x <= 9.5.8 fail to limit access to channels files that have not been linked to a post which allows an attacker to view them in channels that they are a member of.
Weakness: CWE-863
Which versions are affected by CVE-2024-9155?
It affects 1 product.
Products include Mattermost Mattermost Server.
How do I fix CVE-2024-9155?
No fix has been published for CVE-2024-9155 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2024-9155 being exploited?
There is no known exploitation of CVE-2024-9155 in the wild and no public exploit code.
Other vulnerabilities in Mattermost Mattermost Server
- CVE-2025-12419 Account takeover on OAuth/OpenID-enabled servers
- CVE-2025-12421 Account Takeover via Code Exchange Endpoint
- CVE-2025-4981 Path Traversal Leading to RCE by Any Authenticated Mattermost User
- CVE-2025-20051 Arbitrary file read via block duplication in Mattermost Boards
- CVE-2025-25279 Arbitrary file read in Mattermost Boards via import & export board archive
Sources
Also known as GHSA-h287-xx77-94v5.