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)

Published · last modified .

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.

EPSS exploit prediction

EPSS: 0.015 (73.9th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 74th percentile — 73.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-3854: fell from 0.400 to 0.015.

EPSS over last 30 days · oldest: 0.400 · newest: 0.015 · change: -0.385

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.