CVE-2026-5921— Server-Side Request Forgery in GitHub Enterprise Server allowed extraction of sensitive environment variables via timing side-channel attack

Server-Side Request Forgery in GitHub Enterprise Server allowed extraction of sensitive environment variables via timing side-channel attack

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.

N/A

服务端请求伪造(SSRF)

GitHub Enterprise Server 安全漏洞

GitHub Enterprise Server是美国GitHub开源的一个应用软件。提供一个将自己的GitHub实例设置为虚拟设备，从而提供可扩展，易于管理的平台。 GitHub Enterprise Server 3.21之前版本存在安全漏洞，该漏洞源于笔记本渲染服务存在服务端请求伪造，可能导致攻击者通过定时侧信道攻击提取敏感环境变量。

N/A

N/A