Server-side request forgery vulnerability in GitHub Enterprise Server notebook viewer via URL parser confusion
Summary
| CVE | CVE-2026-8034 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_P |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-07 22:16:37 UTC |
| Updated | 2026-05-07 22:16:37 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v4.0 7.9 HIGH from [email protected]
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
Problem Types: CWE-436 | CWE-918 | CWE-918 CWE-918 Server-Side request forgery (SSRF) | CWE-436 CWE-436 Interpretation Conflict
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 7.9 | HIGH | 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/C... |
| 4.0 | CNA | CVSS | 7.9 | HIGH | 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 |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
NonePrivileges Required
NoneUser Interaction
NoneConfidentiality
NoneIntegrity
NoneAvailability
NoneSub Conf.
HighSub Integrity
HighSub Availability
HighCVSS: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
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | GitHub | Enterprise Server | affected 3.16.0 3.16.17 semver | Not specified |
| CNA | GitHub | Enterprise Server | affected 3.17.0 3.17.14 semver | Not specified |
| CNA | GitHub | Enterprise Server | affected 3.18.0 3.18.8 semver | Not specified |
| CNA | GitHub | Enterprise Server | affected 3.19.0 3.19.5 semver | Not specified |
| CNA | GitHub | Enterprise Server | affected 3.20.0 3.20.1 semver | Not specified |
| CNA | GitHub | Enterprise Server | unaffected 3.21.0 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 | |
| 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.