RCE in GitHub Enterprise Server

CVE-2026-3854

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.

Vulnerability class: Command Injection (OS Command Injection)

EPSS: 0.400 (98.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-3854?
CVE-2026-3854 is a high-severity vulnerability in GitHub Enterprise Server, classified under Command Injection. CVSS score: 8.8/10. Published 2026-03-10.
How severe is CVE-2026-3854?
High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2026-3854 known to be exploited?
10 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.