CVE-2026-8606: GitHub Enterprise Server

Medium severity, CVSS 5.9. EPSS: 0.7% chance of exploitation in the next 30 days.

A Server-Side Request Forgery (SSRF) vulnerability was identified in GitHub Enterprise Server that allowed an attacker to cause the server to issue HTTP requests to internal services via the security advisories package lookup feature. By directing requests to an internal management service and measuring response timing, an attacker could infer the values of sensitive environment variables, including signing secrets and private keys. Exploitation required GitHub Packages to be enabled; on instances not running in private mode the vulnerability was exploitable without authentication, otherwise any authenticated user could exploit it. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21.1 and was fixed in versions 3.20.3, 3.19.7, 3.18.10, 3.17.16, and 3.16.19. This vulnerability was reported via the GitHub Bug Bounty program.

Affected products

• GitHub Enterprise Server: before 3.16.19 (fixed in 3.16.19); from 3.17.0, before 3.17.16 (fixed in 3.17.16); from 3.18.0, before 3.18.10 (fixed in 3.18.10); from 3.19.0, before 3.19.7 (fixed in 3.19.7); from 3.20.0, before 3.20.3 (fixed in 3.20.3); version 3.21.0 only

Published 2026-05-27. Last modified 2026-07-23.