CVE-2026-8606 json
Server-Side Request Forgery in GitHub Enterprise Server via Advisory Package URL Endpoint
published 2026-05-26 5 mo ago modified 2026-07-23 3 mo ago also EUVD-2026-32025
- cvss
- 5.9
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 42%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- GitHub Enterprise Server 3.16.19, 3.17.16, 3.18.10, 3.19.7, 3.20.3, 3.21.1
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 5 mo ago
Exploit prediction
0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 7.0 | 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 |
| CNA | 4.0 | 7.0 | 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 |
| NVD | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
Affected products
- GitHub Enterprise Server
Classification
- Weakness
-
- CWE-918 Server-Side Request Forgery
References
-
docs.github.com
/en/enterprise-server@3.21/admin/release-notes#3.21.1
release-notes, product
-
docs.github.com
/en/enterprise-server@3.20/admin/release-notes#3.20.3
release-notes, product
-
docs.github.com
/en/enterprise-server@3.19/admin/release-notes#3.19.7
release-notes, product
-
docs.github.com
/en/enterprise-server@3.18/admin/release-notes#3.18.10
release-notes, product
-
docs.github.com
/en/enterprise-server@3.17/admin/release-notes#3.17.16
release-notes, product
-
docs.github.com
/en/enterprise-server@3.16/admin/release-notes#3.16.19
release-notes, product
Sources
- CVE List CVE-2026-8606
- NVD CVE-2026-8606
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.