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GitHub fixes RCE flaw that gave access to millions of private repos

Published on: April 30, 2026

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GitHub fixes RCE flaw that gave access to millions of private repos

Overview:

A critical security vulnerability was identified in GitHub that could allow attackers to execute code on GitHub’s internal systems. This issue could potentially give access to millions of private repositories. GitHub has fixed the vulnerability, but it was considered highly severe due to the level of access it could provide.

Who it impacts:

  • Organizations and developers using:
    • GitHub.com
    • GitHub Enterprise Cloud
    • GitHub Enterprise Server
  • Any users with repositories hosted on affected GitHub platforms
  • Particularly environments where users have push access to repositories

How it impacts:

  • An attacker with valid access (push permission) could:
    • Execute remote code on GitHub backend systems
    • Gain read/write access to private repositories
    • Access sensitive source code across multiple organizations
  • The attack could be triggered using a single malicious git push command
  • Root cause:
    • Improper validation of user input (push options) allowed command injection
  • Due to GitHub’s shared infrastructure, this could lead to cross-tenant data exposure

CVE Details:

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CVECVSSSeverity
CVE-2026-38548.8High

Affected Versions:

  • GitHub.com (Cloud):
    The vulnerability affected GitHub’s cloud infrastructure however, it has already been fully remediated by GitHub. No action is required from customers using GitHub.com.
  • GitHub Enterprise Server (Self-hosted):
    All versions up to and including 3.19.1 are affected by this vulnerability.

Patched Versions:

Customers using GitHub Enterprise Server should upgrade fixed versions or later:

  • 3.14.25 or later
  • 3.15.20 or later
  • 3.16.16 or later
  • 3.17.13 or later
  • 3.18.8 or later
  • 3.19.4 or later
  • 3.20.0 or later

Note: Organizations using GitHub Enterprise Server (self-hosted) are strongly advised to upgrade to the latest patched version immediately to mitigate the risk. Users of GitHub.com (cloud) are not required to take any action, as the issue has already been resolved by GitHub.

Recommendations:

  •  
    • Apply patches/updates immediately (especially for GitHub Enterprise Server)
  •  
    • Regularly review access to private repositories

Reference Links:

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