CVE-2026-4296

8.8 HIGH
Published: April 21, 2026 Modified: April 29, 2026
View on NVD

Description

An incorrect regular expression vulnerability was identified in GitHub Enterprise Server that allowed an attacker to bypass OAuth redirect URI validation. An attacker with knowledge of a first-party OAuth application's registered callback URL could craft a malicious authorization link that, when clicked by a victim, would redirect the OAuth authorization code to an attacker-controlled domain. This could allow the attacker to gain unauthorized access to the victim's account with the scopes granted to the OAuth application. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.1, 3.19.5, 3.18.8, 3.17.14, 3.16.17, 3.15.21, 3.14.26. 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:R/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@3.14/admin/release-notes#3.14.26
Source: product-cna@github.com
Release Notes Vendor Advisory
https://docs.github.com/en/enterprise-server@3.15/admin/release-notes#3.15.21
Source: product-cna@github.com
Release Notes Vendor Advisory
https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.17
Source: product-cna@github.com
Release Notes Vendor Advisory
https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.14
Source: product-cna@github.com
Release Notes Vendor Advisory
https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.8
Source: product-cna@github.com
Release Notes Vendor Advisory
https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.5
Source: product-cna@github.com
Release Notes Vendor Advisory
https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.1
Source: product-cna@github.com
Release Notes Vendor Advisory

7 reference(s) from NVD

Quick Stats

CVSS v3 Score
8.8 / 10.0
EPSS (Exploit Probability)
0.0%
13th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

github