CVE-2026-3854: GitHub Enterprise Server

High severity, CVSS 8.8. EPSS: 1.5% chance of exploitation in the next 30 days.

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.

Affected products

• GitHub Enterprise Server: before 3.14.24 (fixed in 3.14.24); from 3.15.0, before 3.15.19 (fixed in 3.15.19); from 3.16.0, before 3.16.15 (fixed in 3.16.15); from 3.17.0, before 3.17.12 (fixed in 3.17.12); from 3.18.0, before 3.18.6 (fixed in 3.18.6); from 3.19.0, before 3.19.3 (fixed in 3.19.3)

Published 2026-03-10. Last modified 2026-06-17.