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.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 39.8%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
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.
- CVSS 4.0
- 8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 39.80% probability · 99th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-77
- Affected
- github/enterprise server
- Source
- product-cna@github.com
EPSS moved from 1.4% on 24 September 2026 to 39.8% on 30 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
References
- https://docs.github.com/en/enterprise-server@3.14/admin/release-notes#3.14.25
- https://docs.github.com/en/enterprise-server@3.15/admin/release-notes#3.15.20
- https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.16
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.13
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.7
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.4
- https://www.wiz.io/blog/github-rce-vulnerability-cve-2026-3854
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.