CVE-2026-76851Network attack vector

Authenticated code execution via internal request redirection

Published Sep 1, 2026 · Updated Sep 2, 2026

SSRF in GitHub Enterprise Server allows remote authenticated users to execute arbitrary code on the instance through pre-receive hooks. Insufficient isolation lets malicious hook code impersonate an internal service and redirect trusted requests to a privileged service. Reachability requires enabled pre-receive-hook networking and authority to configure or modify a repository hook.

CVSS severity7.7
High
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in GitHub Enterprise Server allows remote authenticated users to execute arbitrary code on the instance through pre-receive hooks. Insufficient isolation lets malicious hook code impersonate an internal service and redirect trusted requests to a privileged service. Reachability requires enabled pre-receive-hook networking and authority to configure or modify a repository hook.

The record

CVE
CVE-2026-76851
Published
Sep 1, 2026
Updated
Sep 2, 2026
Vendor
Twitter
Product
GitHub Enterprise Server
Classifications
CWE-918, CAPEC-664, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.17.0 <=3.17.19 changes=[{"at":"3.17.20","status":"unaffected"}]
  2. Affected versionversion=3.18.0 <=3.18.13 changes=[{"at":"3.18.14","status":"unaffected"}]
  3. Affected versionversion=3.19.0 <=3.19.10 changes=[{"at":"3.19.11","status":"unaffected"}]
  4. Affected versionversion=3.20.0 <=3.20.6 changes=[{"at":"3.20.7","status":"unaffected"}]
  5. Affected versionversion=3.21.0 <=3.21.4 changes=[{"at":"3.21.5","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Twitter · GitHub Enterprise Serverversion=3.17.0 <=3.17.19 changes=[{"at":"3.17.20","status":"unaffected"}]; version=3.18.0 <=3.18.13 changes=[{"at":"3.18.14","status":"unaffected"}]; version=3.19.0 <=3.19.10 changes=[{"at":"3.19.11","status":"unaffected"}]; version=3.20.0 <=3.20.6 changes=[{"at":"3.20.7","status":"unaffected"}]; version=3.21.0 <=3.21.4 changes=[{"at":"3.21.5","status":"unaffected"}]

Published CVSS scores

7.7GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
CAPEC-664Server Side Request Forgery
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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