CVE-2026-76851 — Server-Side Request Forgery (SSRF) in Github Enterprise Server
A Server-Side Request Forgery (SSRF) vulnerability was identified in GitHub Enterprise Server that allowed remote code execution on the instance. Insufficient network isolation allowed malicious pre-receive hook code to impersonate an internal service and redirect trusted internal requests to a privileged service, leading to elevated code execution. Exploitation required pre-receive hook networking to be enabled and either site administrator privileges or write access to a repository containing a configured pre-receive hook. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.17.20, 3.18.14, 3.19.11, 3.20.7, and 3.21.5. This vulnerability was reported via the GitHub Bug Bounty program.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Github Enterprise Server).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (ssrf), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Github | Enterprise Server | < 3.17.20≥ 3.18.0 and < 3.18.14≥ 3.19.0 and < 3.19.11≥ 3.20.0 and < 3.20.7≥ 3.21.0 and < 3.21.5 | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.7 | CVSS 4.0 | High | — | — | product-cna@github.com via NIST National Vulnerability Database |
| 8.8 | CVSS 3.1 | High | 2.8 | 5.9 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Monitor outbound requests from the server to internal IPs and cloud metadata endpoints.
Timeline
What happened to this CVE, newest first.
- 2026
- Record published
- CVSS changed · 8.8
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
5 on the record
- docs.github.com/en/enterprise-server@3.17/admin/release-notes
- docs.github.com/en/enterprise-server@3.21/admin/release-notes
- docs.github.com/en/enterprise-server@3.20/admin/release-notes
- docs.github.com/en/enterprise-server@3.19/admin/release-notes
- docs.github.com/en/enterprise-server@3.18/admin/release-notes
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-96890 Server-Side Request Forgery vulnerability was identified in GitHub Enterprise Server that allowed requests to attacker-controlled internal hosts 9d
- Medium CVE-2026-103620 Missing authorization in GitHub Enterprise Server allowed repository writers to replace default branches via GraphQL 9d
- Medium CVE-2026-77912 Cross-site Scripting (XSS) in Github Enterprise Server 23d
- Critical CVE-2026-77987 A server-side request forgery (SSRF) vulnerability was identified in the notebook viewer… 23d
- Medium CVE-2026-75101 Authorization Bypass Through User-Controlled Key (IDOR) in Github Enterprise Server 23d
- High CVE-2026-19118 TOCTOU Race Condition in Github Enterprise Server Sep 1, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- No CISA SSVC assessment.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-76851 is "Server-Side Request Forgery (SSRF) in Github Enterprise Server", rated High. It affects Enterprise Server (Github); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.8 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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