CVE-2026-8034

9.8 CRITICAL
Published: May 07, 2026 Modified: May 11, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.18
Source: product-cna@github.com
Release Notes Vendor Advisory
https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.15
Source: product-cna@github.com
Release Notes Vendor Advisory
https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.9
Source: product-cna@github.com
Release Notes Vendor Advisory
https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.6
Source: product-cna@github.com
Release Notes Vendor Advisory
https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.2
Source: product-cna@github.com
Release Notes Vendor Advisory

5 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.8 / 10.0
EPSS (Exploit Probability)
0.1%
21th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

github