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TI-2026-03739 Aliases CVE-2026-4296GHSA-mcp7-23p7-2v34

Incorrect Regular Expression vulnerability in GitHub Enterprise Server allowed…

Priority LOW 35CWE-185Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Passive
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00426 37th percentileScored 2026-11-07
Fix Fixed Enterprise Server (GitHub): 3.20.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
GitHubEnterprise Server3.14.0 – 3.14.25; 3.15.0 – 3.15.20; 3.16.0 – 3.16.16; 3.17.0 – 3.17.13; 3.18.0 – 3.18.7; 3.19.0 – 3.19.4; 3.20.0 to before 3.20.13.20.1Patch availableCNA
  • Enterprise Server VendorGitHub Affected 3.14.0 – 3.14.25; 3.15.0 – 3.15.20; 3.16.0 – 3.16.16; 3.17.0 – 3.17.13; 3.18.0 – 3.18.7; 3.19.0 – 3.19.4; 3.20.0 to before 3.20.1 Fixed in 3.20.1 Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*before 3.14.26; 3.15.0 to before 3.15.21; 3.16.0 to before 3.16.17; 3.17.0 to before 3.17.14; 3.18.0 to before 3.18.8; 3.19.0 to before 3.19.5VulnerableGitHub
cpe:2.3:a:github:enterprise_server:3.20.0:*:*:*:*:*:*:*3.20.0VulnerableGitHub
  • cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* Versions before 3.14.26; 3.15.0 to before 3.15.21; 3.16.0 to before 3.16.17; 3.17.0 to before 3.17.14; 3.18.0 to before 3.18.8; 3.19.0 to before 3.19.5 Vulnerable ·GitHub
  • cpe:2.3:a:github:enterprise_server:3.20.0:*:*:*:*:*:*:* Versions 3.20.0 Vulnerable ·GitHub

Remediation

  • Fix · CNA Enterprise Server (GitHub) Fixed in 3.20.1

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    GitHub Enterprise Server 3.20.1

    3 records Highest priority Priority LOW 3 LOW

    Other records, highest priority first

    • TI-2026-05124 Improper authorization fallback allows scoped user-to-server token installation escape in GitHub Enterprise ServerPriority LOW 33
    • TI-2026-04829 Improper authorization vulnerability in GitHub Enterprise Server allowed disclosure of…Priority LOW 24
    Show all 3 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-4296
  2. 2026-10-03 Alias added: GHSA-mcp7-23p7-2v34
  3. 2026-10-25 EPSS moved to the below the 50th percentile

References

Advisory 7

  • TI-2024-04632 An authentication bypass vulnerability was present in the GitHub Enterprise Server (GHES)… CVSS 4.0CRITICAL 10.0
  • TI-2024-00181 Unsafe Reflection in Github Enterprise Server leading to Command Injection CVSS 3.1CRITICAL 9.8
  • TI-2024-00466 Privilege Escalation by Code Injection in the Management Console in GitHub Enterprise Server CVSS 3.1HIGH 8.8
  • TI-2026-03340 Remote code execution via git push option injection in GitHub Enterprise Server CVSS 4.0HIGH 8.7
  • TI-2024-08804 Improper signature verification in GitHub Enterprise Server CVSS 4.0CRITICAL 9.5
  • TI-2026-08177 Server-side request forgery in GitHub Enterprise Server CVSS 4.0CRITICAL 9.2
See all 125 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences