Go to homepageCyberStrike

Menu

Star on GitHub · 3.2k
Sign inDownload

CVE-2026-4296

8.8 · HIGH

An incorrect regular expression vulnerability was identified in GitHub Enterprise Server that allowed an attacker to bypass OAuth redirect URI validation.

Published Apr 21, 2026CWE-185EPSS 0.74%

Overview

CVE-2026-4296 is a high-severity vulnerability. It was published on April 21, 2026 and has a CVSS 3.1 base score of 8.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 8.8, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubdocs.github.com/en/[email protected]/admin/release-notes#3.14.26GitHubdocs.github.com/en/[email protected]/admin/release-notes#3.15.21GitHubdocs.github.com/en/[email protected]/admin/release-notes#3.16.17GitHubdocs.github.com/en/[email protected]/admin/release-notes#3.17.14GitHubdocs.github.com/en/[email protected]/admin/release-notes#3.18.8GitHubdocs.github.com/en/[email protected]/admin/release-notes#3.19.5GitHubdocs.github.com/en/[email protected]/admin/release-notes#3.20.1

How CyberStrike helps

Frequently asked questions

What is CVE-2026-4296?

CVE-2026-4296 is a high-severity vulnerability. It was published on April 21, 2026 and has a CVSS 3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-4296?

This vulnerability has a CVSS 3.1 base score of 8.8, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-4296?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-4296?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-4296 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

Related HIGH CVEs from 2026

View all
Browse by year2026202520242023202220212020201920182017201620152014201320122011201020092008200720062005200420032002200120001999