Server-Side Request Forgery in GitHub Enterprise Server via Advisory Package URL Endpoint
Summary
| CVE | CVE-2026-8606 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_P |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-27 00:16:37 UTC |
| Updated | 2026-05-27 00:16:37 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 7 HIGH from [email protected]
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: 0.000760000 probability, percentile 0.226870000 (date 2026-05-27)
Problem Types: CWE-918 | CWE-918 CWE-918 Server-Side request forgery (SSRF)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 7 | HIGH | 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/C... |
| 4.0 | CNA | CVSS | 7 | HIGH | 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 |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
HighAttack Requirements
PresentPrivileges Required
NoneUser Interaction
NoneConfidentiality
LowIntegrity
NoneAvailability
NoneSub Conf.
HighSub Integrity
HighSub Availability
NoneCVSS: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
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | GitHub | Enterprise Server | affected 3.21.0 3.21.1 semver | Not specified |
| CNA | GitHub | Enterprise Server | affected 3.20.0 3.20.2 semver | Not specified |
| CNA | GitHub | Enterprise Server | affected 3.19.0 3.19.6 semver | Not specified |
| CNA | GitHub | Enterprise Server | affected 3.18.0 3.18.9 semver | Not specified |
| CNA | GitHub | Enterprise Server | affected 3.17.0 3.17.15 semver | Not specified |
| CNA | GitHub | Enterprise Server | affected 3.16.0 3.16.18 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| docs.github.com/en/[email protected]/admin/release-notes | [email protected] | docs.github.com | |
| docs.github.com/en/[email protected]/admin/release-notes | [email protected] | docs.github.com | |
| docs.github.com/en/[email protected]/admin/release-notes | [email protected] | docs.github.com | |
| docs.github.com/en/[email protected]/admin/release-notes | [email protected] | docs.github.com | |
| docs.github.com/en/[email protected]/admin/release-notes | [email protected] | docs.github.com | |
| docs.github.com/en/[email protected]/admin/release-notes | [email protected] | docs.github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: R31n (en)
There are currently no legacy QID mappings associated with this CVE.