CVE-2026-8034
CRITICALDescription
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 v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 29% of all known CVEs.
References
- https://docs.github.com/en/[email protected]/admin/release-notes#3.16.18
- https://docs.github.com/en/[email protected]/admin/release-notes#3.17.15
- https://docs.github.com/en/[email protected]/admin/release-notes#3.18.9
- https://docs.github.com/en/[email protected]/admin/release-notes#3.19.6
- https://docs.github.com/en/[email protected]/admin/release-notes#3.20.2
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-11.