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A researcher disclosed a four-vulnerability chain that enabled unauthenticated remote code execution on GitHub Enterprise versions before 2.8.7. The attack began with a WebHook server-side request forgery (SSRF) bypass using an unusual IP-address representation to evade Faraday restrictions, then used a second SSRF flaw to reach the internal Graphite service.
A CRLF injection in Python's HTTPConnection allowed protocol smuggling to internal Memcached, where an attacker could plant a malicious Ruby Marshal object in cache. When GitHub Enterprise deserialized the poisoned object, it executed attacker-controlled commands. GitHub validated the report and released version 2.8.7, adding SSRF and internal network-access protections.
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3 events from the most recent confirmed update back to the earliest known activity.
GitHub confirmed the vulnerability chain was fixed and awarded the researcher a $7,500 bounty plus a $5,000 best-report bonus.
GitHub released GitHub Enterprise 2.8.7 to remediate the reported exploit chain, including protections against the SSRF and internal-service access paths used in the attack.
A researcher submitted HackerOne report 200542 to GitHub describing a four-vulnerability chain that could lead from WebHook SSRF to remote code execution in GitHub Enterprise versions before 2.8.7.
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GitHub released urgent security updates for GitHub Enterprise Server to fix multiple severe vulnerabilities affecting versions `3.16` through `3.20`, led by **CVE-2026-9312**, a critical pre-authentication SSRF flaw in an upload endpoint. The bug allowed unauthenticated attackers to craft requests with path traversal content and force the appliance to make internal HTTP requests, potentially exposing internal services, credentials, and configuration data. GitHub said the issue was reported through its bug bounty program and remediated in `3.16.20`, `3.17.17`, `3.18.11`, `3.19.8`, `3.20.4`, and `3.21.1`. The updates also address the high-severity Linux kernel local privilege-escalation flaws **CVE-2026-43284** and **CVE-2026-43500**, known as **Dirty Frag**, which could let a local user gain root on vulnerable appliances. Additional fixes and hardening cover a timing side-channel issue and another SSRF-related weakness tied to package and notebook-related functionality, including environments with GitHub Packages enabled or private mode disabled. GitHub revoked the signing key for GHES release packages and instructed administrators to rotate trusted local GPG public keys before installing the patched releases, urging rapid upgrades for internet-facing and shared multi-tenant deployments.
Jul 20, 2026
A vulnerability tracked as **`CVE-2024-0200`** allowed attackers with organization owner privileges to abuse an unsafe Ruby `Kernel#send()` call in GitHub’s organization repository settings flow and invoke unintended zero-argument methods on `Repository` objects. Researchers showed the bug could be used to trigger `Repository::GitDependency#nw_fsck()` and leak roughly **2 MB of environment variables** from a production GitHub.com container, exposing access keys, secrets, and internal configuration because spawned git processes inherited the parent environment. The issue affected **GitHub.com** and **GitHub Enterprise Server (GHES)** instances with GitHub Actions enabled, but the impact was more severe on GHES. STAR Labs reported that leaked variables on GHES could include `ENTERPRISE_SESSION_SECRET` and other Marshal-related secrets, which could be chained with forged Rails session cookies and an unsafe `Marshal.load` path to achieve **remote code execution**. GitHub hotfixed GitHub.com on December 26, 2023, and later released a patch and advisory, while recommended mitigations included allowlisting the `rid_key` parameter, reducing environment variables passed to git processes, rotating exposed secrets, and monitoring `repository_items` requests for abnormal `rid_key` values.
Jun 29, 2026
GitHub disclosed and patched **CVE-2026-3854**, a critical command-injection flaw in its `git push` pipeline that allowed an authenticated user with repository push access to trigger remote code execution using a single crafted push. Wiz reported the bug on March 4, and GitHub said it reproduced the issue within about 40 minutes and deployed a fix to GitHub.com within roughly two hours, later publishing patches for supported GitHub Enterprise Server releases including **3.14.24, 3.15.19, 3.16.15, 3.17.12, 3.18.6, and 3.19.3**. The vulnerability stemmed from unsanitized user-supplied push option values being inserted into internal `X-Stat` headers, enabling attackers to inject trusted metadata, bypass sandboxing, and execute commands as the `git` service user. Researchers said the flaw could have led to **full server compromise** on GitHub Enterprise Server and, on GitHub.com, code execution on shared storage infrastructure where millions of repositories were accessible to the git service account, creating potential cross-tenant exposure. GitHub said forensic analysis and telemetry found **no evidence of malicious exploitation** and no indication that customer data was accessed, modified, or exfiltrated, but urged Enterprise Server administrators to upgrade immediately and review logs for suspicious push activity. Wiz described the bug as easy to exploit and highlighted its use of AI-assisted reverse engineering tools, including **IDA MCP**, to uncover the issue in GitHub’s closed-source components.
Jul 23, 2026