LiveActive security incident?Get immediate response
CVE Record

CVE-2026-3854: Remote code execution via git push option injection in GitHub Enterprise Server

An 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.

HighCVSS 8.7Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-3854 lets a user who can push to a repository on GitHub Enterprise Server potentially run code on the server. This is serious because repository push access is common in developer environments. GitHub fixed it in multiple supported release lines. No provided source states active exploitation.

Executive priority

Treat as urgent for any self-hosted GitHub Enterprise Server. Prioritize patching because exploitation requires only ordinary repository push privileges, not administrator access. Cloud GitHub.com exposure is not stated in the provided sources.

Technical view

GitHub Enterprise Server improperly sanitized git push option values before placing them in internal service headers. A delimiter conflict allowed crafted input to inject additional metadata fields, leading to remote code execution. The CVSS 4.0 score is 8.7. Affected release lines listed are 3.14.0 through 3.19.0, with fixed versions published by GitHub.

Likely exposure

Organizations running GitHub Enterprise Server versions 3.14.x, 3.15.x, 3.16.x, 3.17.x, 3.18.x, or 3.19.x below the fixed releases are potentially exposed, especially where many users have repository push rights.

Exploitation context

An attacker needs network access to the instance and legitimate push access to at least one repository. The source bundle does not show CISA KEV listing or confirmed exploitation in the wild.

Researcher notes

The core issue is input neutralization in push option handling and internal header construction, categorized as CWE-77. Public sources identify fixed versions but do not provide evidence of active exploitation. Avoid assuming exposure beyond GitHub Enterprise Server release lines named in the CVE data.

Mitigation direction

  • Upgrade GHES 3.14 to 3.14.25 or later in that line.
  • Upgrade GHES 3.15 to 3.15.20 or later in that line.
  • Upgrade GHES 3.16 to 3.16.16 or later in that line.
  • Upgrade GHES 3.17 to 3.17.13 or later in that line.
  • Upgrade GHES 3.18 to 3.18.7 or later in that line.
  • Upgrade GHES 3.19 to 3.19.4 or later in that line.

Validation and detection

  • Inventory all GitHub Enterprise Server appliances and versions.
  • Confirm whether any instance is below the fixed version for its release line.
  • Review repository push permissions, especially broad developer or automation access.
  • Check GitHub release notes for any deployment prerequisites or follow-up guidance.
  • Monitor vendor advisories for updates on exploitation or additional mitigations.
Prepared
Confidence
high
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-77: Command execution behavior lookup

Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-3854 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
8.7 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
8Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.7CVSS 4.0HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——Primary CVE score

Vulnerability scoring details

Base CVSS 4.0 score

8.7High
CVSS 4.0 vector shape for CVE-2026-3854Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
GitHubEnterprise Server3.14.0, 3.15.0, 3.16.0, 3.17.0, 3.18.0, 3.19.0affected
Weakness

CWE details

CWE-77

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-77 · source CWE mapping

Improper Neutralization of Special Elements used in a Command ('Command Injection')

Improper Neutralization of Special Elements used in a Command ('Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs