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

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 29 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

39.8%

Up from 1.5% on 22 Oct 2026.

EPSS score, percentile 98.6 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

8.7 High

CVSS v4.0 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

• 3.14.0 through 3.14.24
• 3.15.0 through 3.15.19
• 3.16.0 through 3.16.15
• 3.17.0 through 3.17.12
• 3.18.0 through 3.18.6
• 3.19.0 through 3.19.3

Unaffected from 3.14.25; from 3.15.20; from 3.16.16; from 3.17.13; from 3.18.7; from 3.19.4

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Versions not listed are: affected.

Versions the record lists as unaffected: 3.14.25, 3.15.20, 3.16.16, 3.17.13, 3.18.7, 3.19.4.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

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 deli…

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-3854 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
• The CVE record was published on 10 Mar 2026.
• The CVE record carries a CVSS v4.0 base score of 8.7 (High), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 39.8% (percentile 98.6), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact total.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

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.

Source: CVE List, as of 29 Oct 2026. About the data.

Timeline