CVE-2026-70493

Open WebUI: Any authenticated user can stall a worker via a knowledge-search pattern that backtracks catastrophically

MEDIUM
6.5
CVSS Score
Published: August 4, 2026 at 08:56 PM UTC
Updated: September 18, 2026 at 02:59 PM UTC
1 product affected across 1 vendorOpen Webui

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.6%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.11.00.9.6 ≤ v < 0.11.0
Affected range stops below 0.11.0, so it looks safe — our inference, not a vendor statement

References (4)

x_refsource_CONFIRMExploitPatchVendor Advisory
Source: cverecord
https://github.com/open-webui/open-webui/security/advisories/GHSA-2f54-p244-32q6
x_refsource_MISCPatchVendor Advisory
Source: cverecord
https://github.com/open-webui/open-webui/pull/27471
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/open-webui/open-webui/releases/tag/v0.11.0

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-1333

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