CVE-2026-4296: Incorrect Regular Expression vulnerability in GitHub Enterprise Server allowed unauthorized access to user accounts via OAuth callback URL validation bypass
GitHub · Enterprise Server
Vendor fix available · Affected: GitHub Enterprise Server · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 37% of scored CVEs
DescriptionCVE.org
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.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- GitHub · Enterprise Serverfrom 3.14.0 up to and including 3.14.25; from 3.15.0 up to and including 3.15.20; from 3.16.0 up to and including 3.16.16; from 3.17.0 up to and including 3.17.13; from 3.18.0 up to and including 3.18.7; from 3.19.0 up to and including 3.19.4 and 1 more
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- GitHub
- Published
- April 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-4296 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.