CVE-2026-14340
Vulnérabilité moyenne dans Enterprise Server (GitHub)
Description
An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed a user-to-server token scoped to a GitHub App installation to perform certain write operations on public repositories outside the token's intended scope. This was possible because the authorization check only verified that the installation had read permissions on the target repository rather than verifying that the token's installation was explicitly granted access to that repository. An attacker who obtained a victim's user-to-server token could create issues, issue comments, commit comments, and private vulnerability reports on any public repository, appearing as the victim user with no indication of the app involvement. This vulnerability was fixed by adding a repository scope check for user-to-server tokens issued by global apps. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.21.2, 3.20.4, 3.19.8, 3.18.11, 3.17.17, 3.16.20. This vulnerability was reported via the GitHub Bug Bounty program.
Gravité et risque d'exploitation
CVE-2026-14340 obtient un score CVSS de 5.3/10, soit une gravité moyenne. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.43 %, ce qui la place devant 35.6 % des CVE référencées.
Que faire ?
- Vérifiez si Enterprise Server (versions <=3.19.7, 3.16.0, <=3.18.10, 3.21.0, 3.18.0, <=3.16.19, 3.17.0, 3.20.0, 3.19.0, <=3.20.3, <=3.21.1, <=3.17.16) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.
Références
- https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.20
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.17
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.11
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.8
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.4
- https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.2