Github: >> Enterprise Server >> 3.15.20 Security Vulnerabilities
A server-side request forgery (SSRF) vulnerability was identified in GitHub Enterprise Server that allowed an attacker to extract sensitive environment variables from the instance through a timing side-channel attack against the notebook rendering service. When private mode was disabled, the notebook viewer followed HTTP redirects without revalidating the destination host, enabling an unauthenticated SSRF to internal services. By chaining this with regex filter queries against an internal API and measuring response time differences, an attacker could infer secret values character by character. Exploitation required that private mode be disabled and that the attacker be able to chain the instance's open redirect endpoint through an external redirect to reach internal services. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.14.26, 3.15.21, 3.16.17, 3.17.14, 3.18.8, 3.19.5, and 3.20.1. This vulnerability was reported via the GitHub Bug Bounty program.
CVSS Score
8.9
EPSS Score
0.001
Published
2026-04-21
An Incorrect Authorization vulnerability was identified in GitHub Enterprise Server that allowed an authenticated user with a classic personal access token (PAT) lacking the repo scope to retrieve issues and commits from private and internal repositories via the search REST API endpoints. The user must have had existing access to the repository through organization membership or as a collaborator for the vulnerability to be exploitable. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.16.15, 3.17.12, 3.18.6 and 3.19.3. This vulnerability was reported via the GitHub Bug Bounty program.
CVSS Score
5.3
EPSS Score
0.0
Published
2026-03-10
An improper neutralization of input vulnerability was identified in GitHub Enterprise Server that allowed DOM-based cross-site scripting via task list content. The task list content extraction logic did not properly re-encode browser-decoded text nodes before rendering, allowing user-supplied HTML to be injected into the page. An authenticated attacker could craft malicious task list items in issues or pull requests to execute arbitrary scripts in the context of another user's browser session. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.18.6 and 3.19.3. This vulnerability was reported via the GitHub Bug Bounty program.
CVSS Score
7.4
EPSS Score
0.0
Published
2026-03-10
An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed an attacker to merge their own pull request into a repository without having push access by exploiting an authorization bypass in the enable_auto_merge mutation for pull requests. This issue only affected repositories that allow forking as the attack relies on opening a pull request from an attacker-controlled fork into the target repository. Exploitation was only possible in specific scenarios. It required a clean pull request status and only applied to branches without branch protection rules enabled. This vulnerability affected GitHub Enterprise Server versions prior to 3.19.2, 3.18.5, and 3.17.11, and was fixed in versions 3.19.2, 3.18.5, and 3.17.11. This vulnerability was reported via the GitHub Bug Bounty program.
CVSS Score
7.1
EPSS Score
0.0
Published
2026-02-18