CVE-2026-109298 Open WebUI 0.11.0 before 0.11.4 Memory Exhaustion via Knowledge Search Regex
Authenticated users can cause denial of service in Open WebUI by submitting regex patterns that exhaust memory and block the event loop.
- 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-2026-109298?
CVE-2026-109298 is a high-severity denial of service vulnerability in open-webui, published on 12 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Open WebUI 0.11.0 before 0.11.4 compiles user-chosen grep patterns for its knowledge and chat file search tools with a regex engine that expands nested counted repetition unbounded at compile time and caches the result. Authenticated users can have the model call grep_knowledge_files with short nested-repetition patterns, blocking the event loop and exhausting worker memory.
Which versions are affected by CVE-2026-109298?
How do I fix CVE-2026-109298?
No fix has been published for CVE-2026-109298 yet. Limit exposure of the affected software until one is available.
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-2026-109298 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-109298 exists.
Sources
Also known as GHSA-gww9-mhgj-pfqh, GHSA-x55j-pj79-2cgm.