Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-87011— Open WebUI: Unauthenticated requests can stall the server via uncached OIDC fetches in back-channel logout

Quick assessment

Affected
open-webui open-webui
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Open WebUI是Open WebUI团队开源的一个可扩展、功能丰富、用户友好的自托管 WebUI。 Open WebUI 0.9.0版本至0.11.1之前版本存在资源管理错误漏洞，该漏洞源于文件 backend/open_webui/utils/oauth.py 中未认证的 POST /oauth/backchannel-logout 处理程序在验证注销令牌之前获取 OIDC 发现文档和签名密钥，且每个请求重复未缓存的网络获取并阻塞异步事件循环，可能导致携带无效令牌的请求使单工作线程实例停滞，并放大

CVSS 7.5 · High EPSS 0.64% · P50

Possible ATT&CK Techniques 1 AI

T1059 · Command and Scripting Interpreter

Affected Version Matrix 1

VendorProduct Version RangeStatus
open-webui open-webui >= 0.9.0, < 0.11.1 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-87011

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Open WebUI: Unauthenticated requests can stall the server via uncached OIDC fetches in back-channel logout
Source: CVE Program / CVE List V5
Vulnerability Description
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.0 until 0.11.1, the unauthenticated POST /oauth/backchannel-logout handler in backend/open_webui/utils/oauth.py fetched the OIDC discovery document and signing keys before validating a submitted logout token. Each request repeated uncached network fetches, and the signing-key lookup blocked the async event loop, so requests carrying invalid tokens could stall the single-worker instance and amplify traffic to the identity provider when ENABLE_OAUTH_BACKCHANNEL_LOGOUT was enabled. This issue is fixed in version 0.11.1.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
不对称的资源消耗(放大攻击)
Source: CVE Program / CVE List V5
Vulnerability Title
Open WebUI 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Open WebUI是Open WebUI团队开源的一个可扩展、功能丰富、用户友好的自托管 WebUI。 Open WebUI 0.9.0版本至0.11.1之前版本存在资源管理错误漏洞，该漏洞源于文件 backend/open_webui/utils/oauth.py 中未认证的 POST /oauth/backchannel-logout 处理程序在验证注销令牌之前获取 OIDC 发现文档和签名密钥，且每个请求重复未缓存的网络获取并阻塞异步事件循环，可能导致携带无效令牌的请求使单工作线程实例停滞，并放大
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
open-webui open-webui >= 0.9.0, < 0.11.1 -

II. Public POCs for CVE-2026-87011

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-87011

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-87011 (1)

Vendor Advisories for CVE-2026-87011 (1)

Same Patch Batch · open-webui · 2026-09-09 · 16 CVEs total

CVE-2026-87995 8.7 HIGH Open WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcodin
CVE-2026-87016 8.1 HIGH Open WebUI: Sign-in as another user via wildcard characters in the OAuth subject claim on
CVE-2026-87996 7.7 HIGH Open WebUI: SSRF into internal services via DNS rebinding in the Playwright web loader
CVE-2026-87998 7.1 HIGH Open WebUI: Non-admin users can delete admin-owned external knowledge connections via know
CVE-2026-87999 7.1 HIGH Open WebUI: Any authenticated user can reach the Azure platform channel via server-side we
CVE-2026-87015 6.8 MEDIUM Open WebUI: A user's session cookies are sent to tool servers configured for bearer authen
CVE-2026-87014 6.5 MEDIUM Open WebUI: Admin demoted through SSO role sync keeps read and write access to all users'
CVE-2026-88000 6.5 MEDIUM Open WebUI: Any authenticated user can hang the server via message deletion in a cyclic ch
CVE-2026-88002 6.5 MEDIUM Open WebUI: Any authenticated user can hang the server via a cyclic chat message history
CVE-2026-88001 5.0 MEDIUM Open WebUI: Server-side fetches reach blocked and internal hosts via unvalidated HTTP redi
CVE-2026-87012 4.3 MEDIUM Open WebUI: Any authenticated user can suppress calendar alerts instance-wide via a non-nu
CVE-2026-87013 4.3 MEDIUM Open WebUI: Any authenticated user can start a non-terminating request via a folder parent
CVE-2026-87017 4.3 MEDIUM Open WebUI: Inaccessible knowledge bases are exposed through the built-in knowledge tool o
CVE-2026-87994 4.3 MEDIUM Open WebUI: Channel members can overwrite another member's message via the chat completion
CVE-2026-87997 4.3 MEDIUM Open WebUI: Any authenticated user can inject chats into another user's folder via chat co

IV. Related Vulnerabilities

Same product: open-webui
Same vendor: open-webui
Same weakness: CWE-405