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A high-severity vulnerability in GitHub Enterprise Server’s Git push pipeline, CVE-2026-3854, allows an authenticated user with repository push access to execute commands as the git service user outside the normal pre-receive hook sandbox. Rated 8.7 under CVSS 4.0, the flaw lets attackers inject semicolon-delimited fields into internal X-Stat metadata through push options. Last-write-wins parsing allows those fields to override trusted hook-processing configuration, potentially exposing repository data, configuration, and secrets beyond the attacker’s authorized repository.
Wiz reported that GitHub.com shared the underlying vulnerability, creating potential cross-tenant exposure; GitHub stated that researchers did not access other users’ repository contents. GitHub has identified patched Enterprise Server releases, and administrators should prioritize upgrading affected installations. Security teams should review historical push options containing semicolons for suspicious activity, preserve relevant evidence, investigate potential repository or credential exposure, and rotate potentially exposed secrets where warranted.
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3 events from the most recent confirmed update back to the earliest known activity.
GitHub identified GHES 3.14.25, 3.15.20, 3.16.16, 3.17.13, 3.18.7, 3.19.4, and 3.20.0 as the minimum patched builds for their respective release branches. It recommended reviewing /var/log/github-audit.log for push options containing semicolons and investigating suspicious activity rather than treating every match as proof of exploitation.
GitHub stated that researchers accessed repository records to validate the vulnerability but did not access other users' repository contents.
Wiz reported that the vulnerability affected both GitHub Enterprise Server and GitHub.com, creating potential cross-tenant exposure. An authenticated user with repository push access could inject internal metadata through Git push options, override hook-processing settings, and execute commands outside the normal sandbox as the git service user.
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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
GitHub awarded researcher Saif Ghani a **$100,000** bug bounty for reporting `CVE-2026-3854`, a critical remote-code-execution vulnerability in its Git push processing pipeline. The flaw reportedly enabled an unauthenticated attacker to supply a specially crafted repository URL during Git-related operations and execute arbitrary commands on GitHub backend infrastructure. GitHub said it deployed mitigations shortly after receiving the report and completed a patch rollout through coordinated disclosure before detailed exploitation information became broadly available. Exploitation could have threatened public and private repository integrity, source-code confidentiality, Git objects, secrets and credentials, build workflows, and the wider software supply chain.
Sep 14, 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