cvedb.io
CVE-2026-8034
CRITICAL · CVSS 9.8
EPSS exploitation probability: 0%
Published 2026-05-07T22:16:37.230 · Last modified 2026-06-17T11:03:24.550

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.

Affected products

github — enterprise_server

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.