The vulnerability is a server‑side request forgery that allows an unauthenticated user to instruct the Manage API to send gateway‑to‑agent requests to an attacker‑controlled host. The bearer token in these requests is authenticated only by a timestamp, so a network element that can capture the outbound traffic can reuse the token to authenticate against privileged management‑agent endpoints, effectively granting the attacker elevated control over the GitHub Enterprise Server infrastructure. This weakness is categorized as CWE‑918.

All releases of GitHub Enterprise Server before 3.22 are affected. The advisory lists the specific patch releases: 3.17.19, 3.18.13, 3.19.10, 3.20.6, and 3.21.4, which contain the fix. High‑availability deployments are not impacted because the topology restriction prevented the exploit.

The problem carries a CVSS score of 8.2, indicating a high severity. No EPSS score was provided, and the vulnerability is not currently listed in CISA’s KEV catalog. Since the exploit requires an unauthenticated endpoint to deliver a crafted cluster configuration and the ability to intercept outbound traffic, the practical attack scope is limited to environments with unsecured network paths. The likely attack vector involves sending a malicious request to the vulnerable Manage API endpoint and then capturing the gateway‑to‑agent call, before replaying the token to the management‑agent endpoint.