CVE-2026-4821: CWE-78 Improper neutralization of special elements used in an OS command ('OS command injection') in GitHub Enterprise Server
CVE-2026-4821 is a high-severity vulnerability in GitHub Enterprise Server that allows an authenticated Management Console administrator to execute arbitrary OS commands via shell metacharacter injection in proxy configuration fields such as http_proxy. This vulnerability affects all versions prior to 3. 21 and requires administrator privileges on the Management Console. It was fixed in versions 3. 20. 1, 3. 19. 5, 3. 18. 8, 3.
AI Analysis
Technical Summary
An OS command injection vulnerability (CWE-78) exists in GitHub Enterprise Server's Management Console proxy configuration fields, allowing authenticated administrators to execute arbitrary OS commands via shell metacharacter injection. This affects all versions prior to 3.21. The vulnerability requires high privileges (administrator access) and local access to the server instance. It was addressed by GitHub in multiple patch releases starting with version 3.14.26 and later versions up to 3.20.1. The CVSS 4.0 base score is 8.1, indicating high severity with local attack vector, low attack complexity, no user interaction, and high impact on integrity and availability.
Potential Impact
Successful exploitation allows an authenticated Management Console administrator to execute arbitrary operating system commands on the GitHub Enterprise Server instance. This could lead to full system compromise, data manipulation, or service disruption. However, exploitation requires administrator privileges and access to the server, limiting the attack surface. No public exploits have been reported.
Mitigation Recommendations
This vulnerability is fixed in GitHub Enterprise Server versions 3.20.1, 3.19.5, 3.18.8, 3.17.14, 3.16.17, 3.15.21, and 3.14.26. Administrators should upgrade to one of these patched versions to remediate the issue. Since this is not a cloud service, patching the affected server instances is required. No alternative mitigations or temporary fixes are documented.
CVE-2026-4821: CWE-78 Improper neutralization of special elements used in an OS command ('OS command injection') in GitHub Enterprise Server
Description
CVE-2026-4821 is a high-severity vulnerability in GitHub Enterprise Server that allows an authenticated Management Console administrator to execute arbitrary OS commands via shell metacharacter injection in proxy configuration fields such as http_proxy. This vulnerability affects all versions prior to 3. 21 and requires administrator privileges on the Management Console. It was fixed in versions 3. 20. 1, 3. 19. 5, 3. 18. 8, 3.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
An OS command injection vulnerability (CWE-78) exists in GitHub Enterprise Server's Management Console proxy configuration fields, allowing authenticated administrators to execute arbitrary OS commands via shell metacharacter injection. This affects all versions prior to 3.21. The vulnerability requires high privileges (administrator access) and local access to the server instance. It was addressed by GitHub in multiple patch releases starting with version 3.14.26 and later versions up to 3.20.1. The CVSS 4.0 base score is 8.1, indicating high severity with local attack vector, low attack complexity, no user interaction, and high impact on integrity and availability.
Potential Impact
Successful exploitation allows an authenticated Management Console administrator to execute arbitrary operating system commands on the GitHub Enterprise Server instance. This could lead to full system compromise, data manipulation, or service disruption. However, exploitation requires administrator privileges and access to the server, limiting the attack surface. No public exploits have been reported.
Mitigation Recommendations
This vulnerability is fixed in GitHub Enterprise Server versions 3.20.1, 3.19.5, 3.18.8, 3.17.14, 3.16.17, 3.15.21, and 3.14.26. Administrators should upgrade to one of these patched versions to remediate the issue. Since this is not a cloud service, patching the affected server instances is required. No alternative mitigations or temporary fixes are documented.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_P
- Date Reserved
- 2026-03-25T13:55:26.048Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69e7faaa19fe3cd2cd0014a4
Added to database: 4/21/2026, 10:31:06 PM
Last enriched: 4/21/2026, 10:46:12 PM
Last updated: 4/22/2026, 1:44:11 AM
Views: 7
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