GitHub Enterprise Server patches critical SSRF and Dirty Frag privilege escalation flaws
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.
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How this story unfolded
4 events from the most recent confirmed update back to the earliest known activity.
GitHub removes vulnerable package endpoint to mitigate timing leak
GitHub mitigated the timing side-channel issue affecting the security advisories package lookup feature by removing the vulnerable package endpoint. The flaw could leak sensitive environment variables on servers with GitHub Packages enabled.
GitHub revokes GHES package signing key and requires key rotation
Alongside the GHES security updates, GitHub revoked the signing key used for GHES release packages and instructed administrators to rotate trusted local GPG public keys before validating or installing patched releases. The requirement was presented as part of the remediation guidance for affected deployments.
GitHub releases GHES security updates for multiple severe flaws
GitHub released security updates for GitHub Enterprise Server to fix multiple vulnerabilities affecting versions 3.16 through 3.20, including the critical pre-authentication SSRF flaw CVE-2026-9312 and the Dirty Frag local privilege-escalation issues. Patched versions cited include 3.16.20, 3.17.17, 3.18.11, 3.19.8, 3.20.4, and 3.21.1, while one report also highlights release 3.20.3 as a security-focused patch.
GitHub Bug Bounty report identifies CVE-2026-9312 in GHES
The SSRF vulnerability CVE-2026-9312 in GitHub Enterprise Server was reported through the GitHub Bug Bounty program. The flaw allowed an unauthenticated attacker to send crafted requests to internal services via an upload endpoint.
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GitHub security advisory (AV26-512) - Canadian Centre for Cyber Security
cyber.gc.ca
Open sourceGitHub Enterprise Server 3.20.3 Released With Fox for Critical Vulnerabilities
cybersecuritynews.com
Open sourceGitHub Enterprise Server Vulnerabilities Patched • Daily CyberSecurity
securityonline.info
Open sourceCVE-2026-9312 - Server-Side Request Forgery vulnerability in GitHub Enterprise Server allowed access to internal services via path traversal in upload endpoint
cvefeed.io
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GitHub Patched Critical `git push` RCE Affecting Cloud and Enterprise Server
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.
May 6, 2026
GitHub `Kernel#send()` Flaw Exposed Secrets and Enabled GHES RCE Path
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.
Apr 19, 2026
GitLab patches 11 flaws including account takeover and XSS in CE and EE
GitLab released **19.0.2**, **18.11.5**, and **18.10.8** for self-managed Community Edition and Enterprise Edition deployments to fix **11 security vulnerabilities** and additional bugs, and urged administrators to upgrade immediately. The advisory says all versions before those releases are affected, while **GitLab.com** has already been patched and **GitLab Dedicated** customers do not need to take action. GitLab also warned that the update includes database migrations that may cause downtime on single-node instances, though multi-node environments can use zero-downtime upgrade procedures. The most severe issue, **`CVE-2026-6552`** (**CVSS 8.7**), is an improper authorization flaw in GitLab EE's Group SAML identity management that could let an authenticated **group Owner** take over another group member's account under certain conditions. GitLab also fixed **`CVE-2026-10087`**, an Analytics Dashboard cross-site scripting flaw in GitLab EE that could allow an authenticated **developer** to execute arbitrary client-side code in a victim's browser. The broader patch set addresses additional risks including denial of service in Grape API JSON parsing, SSRF, unauthorized access to confidential data, and other authorization bypasses, and government and vendor advisories have called on organizations to apply the patched versions.
Jun 11, 2026