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CVE-2026-8606

Server-Side Request Forgery in GitHub Enterprise Server via Advisory Package URL Endpoint

Published: May 26, 2026Updated: Jun 1, 2026 Sources: CVE List NVDCWE-918
NVD MITRE
5.9CVSSMEDIUM
EPSS Score
0.4%
Top 69.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

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.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:HI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-918

Affected Products

Enterprise ServerGitHubDevTools & CI
enterprise servergithubDevTools & CI
githubcommercialUSDevTools & CIaka github

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

2 techniques
Command and Control
Initial Access
View detailed technique mapping

References

https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.1
docs.github.com
https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.3
docs.github.com
https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.7
docs.github.com
and 3 more references View all →

Timeline

Published
May 26, 2026
Last Updated
Jun 1, 2026

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