Vulnerability in Open-Webui
CVE-2026-70493
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.6 until 0.11.0, the built-in knowledge search path in backend/open_webui/tools/knowledge_fs.py and backend/open_webui/tools/builtin.py let a chat participant choose a pattern used to grep knowledge files. Patterns containing regex metacharacters were compiled with Python's backtracking re engine and run against every line of every reachable file with no time limit, so a crafted pattern such as (x|x)*y and one matching uploaded file line can pin one CPU core and block the event loop. This causes availability impact for every other user of the affected worker. This issue is fixed in 0.11.0.
Vulnerability class: ReDoS (Regular Expression Denial of Service)
EPSS: 0.003 (23.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Open-webui — versions >= 0.9.6, < 0.11.0
- Openwebui Open_webui
Weakness classification (CWE)
References
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-70493?
- CVE-2026-70493 is a medium-severity vulnerability in Open-Webui, classified under Inefficient Regular Expression Complexity. CVSS score: 6.5/10. Published 2026-08-04.
- How severe is CVE-2026-70493?
- Medium severity. CVSS v3 base score is 6.5 out of 10.