CVE-2026-4296
highpriority · track · 35EPSS 0.004 · 37 %ileDEEUUSEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.8–8.8
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (28)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-1231Microsoft GitHub Enterprise: Mehrere SchwachstellenDeutsch2026-04-21csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Microsoft GitHub Enterprise ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um beliebigen Programmcode auszuführen, und um Informationen offenzulegen.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (15)
External citations — patches, advisories, analysis.
- https://nvd.nist.gov/vuln/detail/CVE-2026-4296cnnvd
- https://docs.github.com/en/enterprise-server@3.14/admin/release-notes#3.14.26enisa_euvd
- https://docs.github.com/en/enterprise-server@3.15/admin/release-notes#3.15.21enisa_euvd
- https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.17enisa_euvd
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.14enisa_euvd
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.8enisa_euvd
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.5enisa_euvd
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.1enisa_euvd
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