CVE-2026-3854
CVE-2026-3854 is a high-severity vulnerability in Github Enterprise Server with a CVSS 3.x base score of 8.8. Its EPSS exploit-prediction score of 24% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-77.
Key facts
- Severity: High (CVSS 3.x base score 8.8)
- CVSS v4: 8.7
- EPSS exploit prediction: 24% (98th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-10744
- Weakness: CWE-77
- Affected product: Github Enterprise Server
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2026-3854?
- CVE-2026-3854 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-3854 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 24% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-3854?
- CVE-2026-3854 affects Github Enterprise Server. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-3854?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-3854 have an EU (EUVD) identifier?
- Yes. CVE-2026-3854 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10744.
- When was CVE-2026-3854 published?
- CVE-2026-3854 was published on 2026-03-10 and last updated on 2026-06-17.
References
- https://docs.github.com/en/[email protected]/admin/release-notes#3.14.25
- https://docs.github.com/en/[email protected]/admin/release-notes#3.15.20
- https://docs.github.com/en/[email protected]/admin/release-notes#3.16.16
- https://docs.github.com/en/[email protected]/admin/release-notes#3.17.13
- https://docs.github.com/en/[email protected]/admin/release-notes#3.18.7
- https://docs.github.com/en/[email protected]/admin/release-notes#3.19.4
- https://www.wiz.io/blog/github-rce-vulnerability-cve-2026-3854
Affected products (1)
- cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*
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