Open WebUI: Cross-user code-interpreter and tool execution via unvalidated Socket.IO event-caller session_id

SummaryAn authenticated low-privilege user can execute arbitrary code-interpreter Python and tools inside another user's authenticated session. The Socket.IO event-caller geteventcall delivers execute:python / execute:tool events to a client-supplied sessionid after only checking that the session...

Open WebUI: Upload `metadata.knowledge_id` bypasses the knowledge-base write-access check (read-only users can add files to KB)

Open WebUI upload metadata can add files to knowledge bases without write permission SummaryOpen WebUI's file upload background processing trusts the client-supplied metadata.knowledgeid value and inserts a knowledgefile association before validating that the uploading user has write access to th...

Open WebUI: ReDoS in skill-mention regexes causes whole-instance DoS on default config

SummaryTwo regexes in backend/openwebui/utils/middleware.py that parse skill-mention tags backtrack in On² on input that contains . Both run synchronously, on the asyncio event loop, on every chat completion with no feature gate. Because the default deployment is a single uvicorn worker, one such...

PYSEC-2026-3596 Open WebUI: ReDoS in skill-mention regexes causes whole-instance DoS on default config

Summary Two regexes in backend/openwebui/utils/middleware.py that parse skill-mention tags backtrack in On² on input that contains . Both run synchronously, on the asyncio event loop, on every chat completion with no feature gate. Because the default deployment is a single uvicorn worker, one suc...

PYSEC-2026-3604 Open WebUI: POST /api/v1/images/edit bypasses the global image-edit switch and the per-user image-generation permission

Summary POST /api/v1/images/edit performed no authorization beyond requiring a verified account. Every other image-editing surface in Open WebUI enforces the global image-edit switch and the per-user image-generation permission — the /api/v1/images/generations route, the built-in editimage tool,...

Open WebUI: Cross-user model-list exposure via static cache key in get_all_models (aiocache key= vs key_builder= misuse)

SummaryThe getallmodels handlers in routers/openai.py and routers/ollama.py intended to cache their permission-filtered model lists per user, but the @cached decorator was misconfigured: it passed a key= lambda instead of keybuilder=. In aiocache 0.12.3 the pinned version, key= is a static cache...

PYSEC-2026-3589 Open WebUI: Cross-user model-list exposure via static cache key in get_all_models (aiocache key= vs key_builder= misuse)

Summary The getallmodels handlers in routers/openai.py and routers/ollama.py intended to cache their permission-filtered model lists per user, but the @cached decorator was misconfigured: it passed a key= lambda instead of keybuilder=. In aiocache 0.12.3 the pinned version, key= is a static cache...

PYSEC-2026-3593 Open WebUI: Upload `metadata.knowledge_id` bypasses the knowledge-base write-access check (read-only users can add files to KB)

Open WebUI upload metadata can add files to knowledge bases without write permission Summary Open WebUI's file upload background processing trusts the client-supplied metadata.knowledgeid value and inserts a knowledgefile association before validating that the uploading user has write access to t...

PYSEC-2026-3595 Open WebUI: Realtime endpoints accept Redis-revoked JWTs after signout/backchannel logout

Summary With Redis configured, Open WebUI supports JWT revocation: POST /api/v1/auths/signout per-token jti and OIDC back-channel logout per-user revokedat record revocations in Redis, and HTTP auth getcurrentuser rejects revoked tokens with 401. The realtime authentication surfaces do not perfor...

PT-2026-67902

Summary A user granted write access to a shared chat folder could permanently delete chats and messages belonging to the folder's owner. Deleting a folder cascades into the owner's chats and the entire subfolder subtree, and the deletion handler required only write access on subfolders instead of...

PT-2026-67924

Summary Open WebUI vetted user-supplied URLs by resolving the hostname once and rejecting private, loopback and link-local addresses, then let the HTTP client resolve that hostname again at connect time. An attacker who controls the authoritative DNS for a hostname they submit can answer with a...

PT-2026-67905

Summary Any authenticated user with access to a terminal server could get script of their choosing to run in the Open WebUI origin itself. The HTML file preview rendered terminal-served files in an iframe whose sandbox always granted allow-same-origin alongside allow-scripts, and the file is serv...

PT-2026-67911

Summary Open WebUI lets a client define a model inline on a chat request instead of selecting a saved workspace model. The knowledge attached to such an inline model was used as-is, without checking that the caller can read what it points at. Any authenticated user who knows another user's file i...

PT-2026-67932

Summary The OAuth token exchange endpoint accepts a raw provider access token and validates it by calling the provider's userinfo endpoint. A userinfo endpoint reports only that a token is valid, never which OAuth client it was issued to, and the endpoint performed no audience or client check of...

PT-2026-67909

Summary The terminal WebSocket route authenticates its own first-message JWT instead of going through the HTTP dependency chain, and never applies the role check that get verified user enforces on every HTTP terminal route. An account whose role is pending, meaning registered but not approved, or...

PT-2026-67929

Summary Any authenticated user can store a chat message whose math block makes KaTeX fail with a stack overflow instead of a parse error. When that happens the renderer falls back to inserting the original math source into the page as HTML rather than as text, so script in the message runs in the...

PT-2026-67900

Summary The built-in knowledge search tools let a chat participant choose the 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 anywhere on that...

PT-2026-67933

Summary With the Playwright web loader enabled, Open WebUI opens user-submitted URLs in a real browser and validates the destination address before allowing the request. That check only ran for the top-level page request. Every other request the page issued was passed through unvalidated, so a pa...

PT-2026-67903

Summary A workspace tool shared with a read grant returned its full Python source to the recipient. Any authenticated non-admin who could use a shared tool could also read its source, including any user on the instance when a tool was shared publicly. Source is meant to be a writer-only tier: the...

PT-2026-67915

Summary Open WebUI fetches user-supplied URLs on the server for RAG URL ingestion, URL-to-markdown conversion and web-search content retrieval, and decides whether a destination is allowed by asking whether its IP address is globally routable. That test operates on the literal IPv6 address and do...