GitHub Enterprise Server EUVD-2026-93667

Exploitation requires: (1) an authenticated user holding push/contributor permission to at least one repository on the instance (PR:L); and (2) the instance must have GitHub Advanced Security enabled WITH secret scanning validity checks turned on - explicitly a non-default configuration. The specific trigger is the GCP service-account credential validator trusting and issuing a request to the token endpoint embedded in a committed credential without restricting the destination. Limiting factors that reduce realistic risk: the attacker must already be an authenticated contributor (not anonymous), the vulnerable feature is off by default so unconfigured instances are not exposed, and only GHES versions 3.20, 3.21, and 3.22 prior to the fixed releases are affected.

This is a genuinely high-severity issue but with meaningful real-world friction that tempers its priority. The vendor CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H, 8.7 High) indicates a network-reachable attack by a low-privileged authenticated user with no interaction and full confidentiality/integrity/availability impact on the vulnerable appliance (SC:N/SI:N/SA:N confirms no spill to a subsequent system in the vendor's modeling, despite the SSRF-to-internal-host chaining). However, several real-risk dampeners are explicit in the description: exploitation requires an authenticated user with push access to a repository (PR:L, not an anonymous internet attacker), AND the appliance must have GitHub Advanced Security with secret scanning validity checks enabled - which GitHub explicitly calls a non-default configuration. No EPSS score, KEV listing, or POC is present in the provided data, so there is no public exploit identified at time of analysis and no evidence of active exploitation. The vulnerability was responsibly disclosed via the GitHub Bug Bounty program rather than discovered in the wild, which is consistent with no observed exploitation. Net assessment: a real and serious vulnerability (SSRF chainable to RCE on the appliance) that warrants prompt patching, but the authentication requirement plus non-default feature prerequisite make opportunistic mass exploitation unlikely; the realistic threat is a malicious or compromised contributor targeting a specifically-configured GHES instance.

A user with push permission to any repository on a GHES instance that has GitHub Advanced Security secret scanning validity checks enabled commits a crafted GCP service-account credential whose embedded token endpoint points at an attacker-chosen internal host. The secret scanning validator trusts that endpoint and issues a request to it from the appliance, giving the attacker SSRF into the internal network that can be chained toward remote code execution on the appliance. No public exploit code was identified in the provided data; the issue was reported through the GitHub Bug Bounty program.