CVE-2026-8034Server-side request forgery vulnerability in GitHub Enterprise Server notebook viewer via URL parser confusion
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.9 HIGH (v4.0, CNA)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
- Weakness (CWE)
- CWE-918, CWE-436
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_P
- NVD analysis
- Analyzed
- Record last updated
- May 8, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
GitHub Enterprise Server github:enterprise_server (from the name) | from 3.16.0 through 3.16.17; fixed at 3.16.18; from 3.17.0 through 3.17.14; fixed at 3.17.15; from 3.18.0 through 3.18.8; fixed at 3.18.9; from 3.19.0 through 3.19.5; fixed at 3.19.6; from 3.20.0 through 3.20.1; fixed at 3.20.2; 3.21.0 not affected | CNA record |
github enterprise_server github:enterprise_server | before 3.16.18; from 3.17.0 before 3.17.15; from 3.18.0 before 3.18.9; from 3.19.0 before 3.19.6; from 3.20.0 before 3.20.2 | NVD |
References
- https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.18release-notes, vendor-advisory
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.15release-notes, vendor-advisory
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.9release-notes, vendor-advisory
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.6release-notes, vendor-advisory
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.2release-notes, vendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.