CVE-2026-70493 Details
Description
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.
A denial-of-service vulnerability has been identified in Open WebUI versions 0.9.6 prior to 0.11.0. The issue arises in the knowledge search feature, where patterns containing regular expression metacharacters are processed by Python's backtracking 're' engine. This unbounded regex matching can be exploited by an authenticated user to pin a CPU core, effectively stalling the event loop and causing availability issues for other users on the same worker. The vulnerability is present in the 'knowledge_fs.py' and 'builtin.py' files.
Users can upgrade to Open WebUI version 0.11.0, where this vulnerability has been fixed. The knowledge search tool now uses the 'regex' engine, which includes a per-search timeout, and every tool call is budgeted to prevent excessive CPU usage.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Aug 5, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/open-webui/open-webui/security/advisories/GHSA-2f54-p244-32q6 | CISA-ADP | ExploitPatchVendor Advisory |
| https://github.com/open-webui/open-webui/commit/3ab2026262ef6f09810e4d235c5f9a9cb903e595 | [email protected] | Patch |
| https://github.com/open-webui/open-webui/pull/27471 | [email protected] | PatchVendor Advisory |
| https://github.com/open-webui/open-webui/releases/tag/v0.11.0 | [email protected] | Release Notes |
| https://github.com/open-webui/open-webui/security/advisories/GHSA-2f54-p244-32q6 | [email protected] | ExploitPatchVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-1333 | Inefficient Regular Expression Complexity | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| openwebui open webui | >= 0.9.6, < 0.11.0 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 18, 2026 | Initial Analysis | [email protected] |
| Aug 5, 2026 | CVE Modified | CISA-ADP |
| Aug 4, 2026 | New CVE Received | [email protected] |