> CVE-2026-5921 [HIGH]

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PUBLISHED
2026-04-21 23:16
MODIFIED
2026-04-21 23:16
CVSS_SCORE V3
8.9
EPSS (Prob. Exploit)
0.65%
Top 49.7%
DATA SOURCES:
NVD 🔗 2026-04-22 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-10-25 GITHUB 🔗 2026-10-29

> DESCRIPTION

A server-side request forgery (SSRF) vulnerability was identified in GitHub Enterprise Server that allowed an attacker to extract sensitive environment variables from the instance through a timing side-channel attack against the notebook rendering service. When private mode was disabled, the notebook viewer followed HTTP redirects without revalidating the destination host, enabling an unauthenticated SSRF to internal services. By chaining this with regex filter queries against an internal API and measuring response time differences, an attacker could infer secret values character by character. Exploitation required that private mode be disabled and that the attacker be able to chain the instance's open redirect endpoint through an external redirect to reach internal services. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.14.26, 3.15.21, 3.16.17, 3.17.14, 3.18.8, 3.19.5, and 3.20.1. This vulnerability was reported via the GitHub Bug Bounty program.

> AFFECTED_PRODUCTS

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

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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
High (H)
Conditions spécifiques doivent être réunies 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
High (H)
Divulgation totale d'informations
I (Impact Intégrité)
Integrity Impact
High (H)
Modification totale des données possible
A (Impact Disponibilité)
Availability Impact
Low (L)
Interruption partielle du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
Low
Interruption partielle du service possible

> WEAKNESSES

CWE-918

> CWE DETAILED DESCRIPTIONS

CWE-918: Server-Side Request Forgery - The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

> GITHUB SECURITY ADVISORY

GHSA-2xwm-4h2q-ggfx MODERATE

Open WebUI: Model meta.knowledge read-only file access can be upgraded to file write/delete

AFFECTED PACKAGES:
PIP / open-webui
>= 0.9.6, < 0.10.0
Fixed in: 0.10.0

> HISTORIQUE DES MODIFICATIONS

Première apparition
21/04/2026 23:16
Source: NVD
📊 ENRICHISSEMENT 01/11/2026 06:59
CWE
Champ modifié: Description CWE
Ancienne valeur:
CWE-918: Server-Side Request Forgery (SSRF) - The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure th...
Nouvelle valeur:
CWE-918: Server-Side Request Forgery - The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the ...
📊 ENRICHISSEMENT 01/05/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-918: Server-Side Request Forgery (SSRF) - The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure th...
Total des modifications: 2 Dernière mise à jour: 1 week ago

> REFERENCES

https://docs.github.com/en/[email protected]/admin/release-notes#3.14.26
https://docs.github.com/en/[email protected]/admin/release-notes#3.15.21
https://docs.github.com/en/[email protected]/admin/release-notes#3.16.17
https://docs.github.com/en/[email protected]/admin/release-notes#3.17.14
https://docs.github.com/en/[email protected]/admin/release-notes#3.18.8
https://docs.github.com/en/[email protected]/admin/release-notes#3.19.5
https://docs.github.com/en/[email protected]/admin/release-notes#3.20.1
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