> CVE-2026-87011 [HIGH]

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PUBLISHED
2026-09-09 21:17
MODIFIED
2026-09-09 21:17
CVSS_SCORE V3
7.5
EPSS (Prob. Exploit)
0.64%
Top 49.7%
DATA SOURCES:
NVD đź”— 2026-09-09 CWE MITRE đź”— 2026-10-01 FIRST EPSS đź”— 2026-10-25 GITHUB đź”— 2026-09-16 OSV đź”— 2026-09-14

> 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.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EXPLOITABILITY
3.9
IMPACT
3.6

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
None (N)
Aucune divulgation d'informations
I (Impact Intégrité)
Integrity Impact
None (N)
Aucune modification de données possible
A (Impact Disponibilité)
Availability Impact
High (H)
Interruption totale du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
None
Aucune divulgation d'informations
Intégrité
None
Aucune modification de données possible
Disponibilité
High
Interruption totale du service possible

> WEAKNESSES

CWE-405 CWE-770

> CWE DETAILED DESCRIPTIONS

CWE-405: Asymmetric Resource Consumption (Amplification) - The product does not properly control situations in which an adversary can cause the product to consume or produce excessive resources without requiring the adversary to invest equivalent work or otherwise prove authorization, i.e., the adversary's influence is "asymmetric." | CWE-770: Allocation of Resources Without Limits or Throttling - The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

> GITHUB SECURITY ADVISORY

GHSA-3g9q-v48f-hh9w HIGH

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

AFFECTED PACKAGES:
PIP / open-webui
>= 0.9.0, <= 0.11.0
Fixed in: 0.11.1

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

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

AFFECTED PACKAGES:
Unknown / Unknown
10 versions affected
ALIASES:
GHSA-3g9q-v48f-hh9w

> HISTORIQUE DES MODIFICATIONS

Première apparition
09/09/2026 21:17
Source: NVD
📊 ENRICHISSEMENT 01/10/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-405: Asymmetric Resource Consumption (Amplification) - The product does not properly control situations in which an adversary can cause the product to consume or produce excessive resources withou...
Total des modifications: 1 Dernière mise à jour: 3 weeks ago

> REFERENCES

https://github.com/open-webui/open-webui/commit/aeda6ff13a25d3b3ba1b303609f35382...
https://github.com/open-webui/open-webui/releases/tag/v0.11.1
https://github.com/open-webui/open-webui/security/advisories/GHSA-3g9q-v48f-hh9w
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