CVE-2026-109295 Open WebUI 0.11.0 before 0.11.4 ReDoS via grep_knowledge_files Event Loop
Authenticated users can cause denial of service in Open WebUI by submitting malicious regex patterns that stall server workers.
- 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-2026-109295?
CVE-2026-109295 is a medium-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 from 0.11.0 before 0.11.4 contains a regular expression denial of service vulnerability that allows authenticated users to stall server workers via file search patterns. Attackers can instruct the model to call grep_knowledge_files or grep_chat_files with a catastrophically backtracking regex, blocking the event loop for two seconds per repeated call.
Weakness: CWE-1333
Which versions are affected by CVE-2026-109295?
How do I fix CVE-2026-109295?
No fix has been published for CVE-2026-109295 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-2026-109295 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-109295 exists.
Sources
Also known as GHSA-9hcw-jmg5-2vcc, GHSA-gfjp-5hc9-852r.