CVE-2026-8034 json
Server-side request forgery vulnerability in GitHub Enterprise Server notebook viewer via URL parser confusion
published 2026-05-07 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-28464
- cvss
- 9.8
- 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 44%
- public exploits
- 0
- none known
Summary
A server-side request forgery (SSRF) vulnerability was identified in the GitHub Enterprise Server notebook viewer that allowed an attacker to access internal services by exploiting URL parser confusion between the validation layer and the HTTP request library. The hostname validation used a different URL parser than the request library, enabling a crafted URL to pass validation while directing the request to an unintended host. Exploitation required network access to the GitHub Enterprise Server instance. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.16.18, 3.17.15, 3.18.9, 3.19.6, and 3.20.2. This vulnerability was reported via the GitHub Bug Bounty program.
Patch / fix
- GitHub Enterprise Server 3.16.18, 3.17.15, 3.18.9, 3.19.6, 3.20.2, 3.21.0
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 6 mo ago
Exploit prediction
0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 7.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H |
| CNA | 4.0 | 7.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H/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 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected products
- GitHub Enterprise Server
Classification
References
-
docs.github.com
/en/enterprise-server@3.16/admin/release-notes#3.16.18
release-notes, vendor-advisory
-
docs.github.com
/en/enterprise-server@3.17/admin/release-notes#3.17.15
release-notes, vendor-advisory
-
docs.github.com
/en/enterprise-server@3.18/admin/release-notes#3.18.9
release-notes, vendor-advisory
-
docs.github.com
/en/enterprise-server@3.19/admin/release-notes#3.19.6
release-notes, vendor-advisory
-
docs.github.com
/en/enterprise-server@3.20/admin/release-notes#3.20.2
release-notes, vendor-advisory
Sources
- CVE List CVE-2026-8034
- NVD CVE-2026-8034
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