CVE-2026-8034
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| github | enterprise_server | {"endExcluding":"3.16.18"} | 3.16.18 |
References
- https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.18
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.15
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.9
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.6
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.2
CWEs
CWE-436 CWE-918
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.