Description
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
References6
- docs.github.com/en/[email protected]/admin/release-notes#3… ProductRelease Notes
- docs.github.com/en/[email protected]/admin/release-notes#3… ProductRelease Notes
- docs.github.com/en/[email protected]/admin/release-notes#3… ProductRelease Notes
- docs.github.com/en/[email protected]/admin/release-notes#3… ProductRelease Notes
- docs.github.com/en/[email protected]/admin/release-notes#3… ProductRelease Notes
- docs.github.com/en/[email protected]/admin/release-notes#3… ProductRelease Notes
Metrics
- CVSS 3.1
-
5.9
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N - CVSS 4.0
-
7.0
HIGH
Score source: CNA
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/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 - EPSS — exploit probability
- 0% percentile: 43 · as of 14 November 2026
- CWE
- CWE-918
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.