CVE-2026-70493
MediumCVSS 6.5Exploitation Probability (EPSS)
Low risk23th percentile - higher than 23% of all known CVEs
Summary
Open WebUI versions 0.9.6 through 0.11.0 have a DoS vulnerability in the knowledge search path. Patterns containing regex metacharacters are compiled with Python's backtracking re engine and run without time limit, allowing an attacker to pin a CPU core and block the event loop. The issue is fixed in version 0.11.0.
Risk Assessment
An attacker can cause service unavailability for all users, leading to downtime and potential financial losses.
Recommendation
Update Open WebUI to version 0.11.0 or later, which includes the fix.
Other vulnerabilities in Open WebUI
See all- CVE-2026-109297Medium
Open WebUI 0.11.0 before 0.11.4 contains a denial of service vulnerability in the automation recurrence-rule validator. Users can submit rules that expand per-second synchronously, blocking the shared event loop for minutes per request and on every scheduler poll.
- CVE-2026-109296Medium
Open WebUI before 0.11.4 contains a missing authorization vulnerability that allows authenticated users to reach disabled model provider backends by supplying an explicit backend index. Attackers can trigger requests carrying configured API keys, read version strings, and enumerate connections.
- CVE-2026-109292Medium
Open WebUI from 0.6.27 before 0.11.4 contains an information disclosure vulnerability that allows destination servers to obtain user session cookies by receiving the full browser cookie jar on OAuth-mode connections. Operators of OpenAI-compatible connections, OpenAPI tool servers or terminal servers can capture forwarded session cookies from routine requests and replay them to hijack accounts, including administrators.
- CVE-2026-109291High
Open WebUI versions from 0.6.33 before 0.11.4 contain a cross-site scripting vulnerability that allows authenticated users to execute script in victims' sessions by storing javascript: URLs in citation embed_url fields. Attackers can share a crafted chat whose citation, when clicked, is passed to window.open, letting them steal localStorage.token and act as the victim.
- CVE-2026-109287Medium
Open WebUI from 0.9.6 before 0.11.4 contains an authorization flaw where the knowledge base file listing does not verify that a supplied directory_id belongs to the requested knowledge base. Users with read access to any knowledge base can supply a retained foreign directory UUID to GET /api/v1/knowledge/{id}/files. The returned breadcrumbs expose folder names, owner user ids and knowledge base ids of that directory and all its ancestors.
- CVE-2026-109286High
Open WebUI from 0.7.0 before 0.11.4 contains a cross-origin message handling vulnerability in SyncStatsModal that allows any website to steal a signed-in user's session token by posting unvalidated verify:chat messages. Attackers can supply a path-traversal chat id redirecting the authenticated stats export request to the auths endpoint, receiving the victim's JWT for full API access.
- CVE-2026-45350High
In Open WebUI prior to version 0.8.6, there is a vulnerability in the chat completion API that allows attackers to bypass tool restrictions, potentially enabling unauthorized actions or access.
- CVE-2026-45338High
In Open WebUI prior to version 0.9.0, a Server-Side Request Forgery (SSRF) vulnerability exists in the _process_picture_url() function, allowing an attacker to force the server to make HTTP requests to internal resources.
- CVE-2026-45315High
Open WebUI prior to version 0.9.3 has a vulnerability that allows audio files with HTML extensions to be uploaded, potentially leading to the execution of malicious code in users' browsers. A user with the appropriate permissions can trick others into opening a malicious link.
- CVE-2026-45303High
Open WebUI is a self-hosted artificial intelligence platform that prior to version 0.6.5 allowed for script injection and execution through the HTML rendering view. The chat content was embedded in an iFrame with sandbox restrictions that were largely ineffective.
Original NVD description (English source)
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 data from NVD (NIST) · CISA KEV · EPSS

