Enterprise ServerApplication · GitHub
CVE-2026-3854
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn improper neutralization of special elements vulnerability was identified in GitHub Enterprise Server that allowed an attacker with push access to a repository to achieve remote code execution on the instance. During a git push operation, user-supplied push option values were not properly sanitized before being included in internal service headers. Because the internal header format used a delimiter character that could also appear in user input, an attacker could inject additional metadata fields through crafted push option values. This vulnerability was reported via the GitHub Bug Bounty program and has been fixed in GitHub Enterprise Server versions 3.14.25, 3.15.20, 3.16.16, 3.17.13, 3.18.7 and 3.19.4.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceIn GitHub Enterprise Server, git push operation handling does not properly sanitize user-supplied push option values before inserting them into internal service headers. Because the header format uses a delimiter character that can also appear in user input, an attacker with push access can inject arbitrary metadata fields by crafting malicious push option values, leading to remote code execution on the instance.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Enterprise ServerApplication
< 3.14.24>= 3.15.0, < 3.15.19>= 3.16.0, < 3.16.15>= 3.17.0, < 3.17.12>= 3.18.0, < 3.18.6>= 3.19.0, < 3.19.3CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Determine GitHub Enterprise Server versionAccess the Management Console and navigate to the 'About' section, or run 'ghe-version' from the administrative SSH shellAffected if The installed version falls within any of the affected ranges: < 3.14.24, >= 3.15.0 and < 3.15.19, >= 3.16.0 and < 3.16.15, >= 3.17.0 and < 3.17.12, >= 3.18.0 and < 3.18.6, or >= 3.19.0 and < 3.19.3
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Identify repositories with push access granted to untrusted usersIn the Management Console, review organization and repository team memberships and collaborator settings. Check which users or teams have 'Write' or 'Admin' access to repositoriesAffected if Repositories allow push access from users who are not fully trusted to execute arbitrary code on the GitHub Enterprise instance
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Verify if git push operations are permittedReview the site admin settings under 'Repository management' to confirm that push operations are not globally disabled for the instanceAffected if Git push operations are enabled and users with push access can execute git push commands against repositories on this instance
The environment is affected if the GitHub Enterprise Server version is within any of the vulnerable ranges listed AND push access is available to users who are not trusted to execute code on the instance.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped3.14.243.15.193.16.15
Update GitHub Enterprise Server to version 3.14.25, 3.15.20, 3.16.16, 3.17.13, 3.18.7, or 3.19.4 or later to patch this vulnerability. Until patched, restrict repository push access to trusted users only.
Upgrade to the latest version in your current release branch: 3.14.25+ (if on 3.14.x), 3.15.20+ (if on 3.15.x), 3.16.16+ (if on 3.16.x), 3.17.13+ (if on 3.17.x), 3.18.7+ (if on 3.18.x), or 3.19.4+ (if on 3.19.x). Prefer 3.19.4 or later for latest security fixes.
- 1. Identify your current GitHub Enterprise Server version by navigating to the Management Console or using the administrative shell.
- 2. Determine which release branch you are on (3.14.x, 3.15.x, 3.16.x, 3.17.x, 3.18.x, or 3.19.x).
- 3. Plan the upgrade: review the release notes for the target fixed version to understand any prerequisites, known issues, or migration requirements.
- 4. Take a complete backup of your GitHub Enterprise Server instance, including database and filesystem data, following standard backup procedures.
- 5. Schedule a maintenance window as GitHub Enterprise Server upgrades typically require downtime.
- 6. Upgrade to the appropriate fixed version based on your current branch: 3.14.25+, 3.15.20+, 3.16.16+, 3.17.13+, 3.18.7+, or 3.19.4+.
- 7. After upgrade, verify the instance is functioning correctly and test git push operations to confirm the vulnerability is resolved.
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Enterprise Server
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-3854 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-3854 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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