CVE-2026-11993 Fix authenticated members disabling file content indexing server-wide via extraction pool exhaustion
Authenticated users can exhaust server resources by uploading heavy files, blocking file content indexing for other users.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-11993?
CVE-2026-11993 is a medium-severity denial of service vulnerability in Mattermost Mattermost Server, published on 14 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to properly enforce the limit of concurrent files being processed and handled failed files, which allows a user with permission to upload files to spawn more goroutines than intended and block the indexing of other files via uploading heavy files constantly to the server.. Mattermost Advisory ID: MMSA-2026-00696
Weakness: CWE-770
Which versions are affected by CVE-2026-11993?
It affects 1 product.
Products include Mattermost Mattermost Server.
How do I fix CVE-2026-11993?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-11993 being exploited?
There is no known exploitation of CVE-2026-11993 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-rx7r-2mx7-mxq9, MINI-7qrc-58x9-vqpw, MINI-px95-96r5-5grc.