Missing authorization in GitHub Enterprise Server
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-862.
Summary
A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed an authenticated user with write access to any repository to read metadata from private repositories they did not have access to, including private repository owners and names, branch names, commit SHAs, commit messages, and the pushing actor. The delegated bypass endpoint resolved a rule suite directly from an attacker-supplied, encoded identifier without verifying that the requesting user could read the rule suite's repository, and because these identifiers are sequential an attacker could enumerate them across the instance. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.17.18, 3.18.12, 3.19.9, 3.20.5, and 3.21.3. This vulnerability was reported via the GitHub Bug Bounty program.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| GitHub | Enterprise Server | 3.17.0 – 3.17.17; 3.18.0 – 3.18.11; 3.19.0 – 3.19.8; 3.20.0 – 3.20.4; 3.21.0 – 3.21.2 | — | No fix listed | CNA |
- Enterprise Server VendorGitHub Affected 3.17.0 – 3.17.17; 3.18.0 – 3.18.11; 3.19.0 – 3.19.8; 3.20.0 – 3.20.4; 3.21.0 – 3.21.2 Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-15783
- 2026-10-03 Alias added: GHSA-qhvh-xjh2-7c8c
References
Other 5
- https://docs.github.com/en/[email protected]/admin/release-notes#3.17.18
- https://docs.github.com/en/[email protected]/admin/release-notes#3.18.12
- https://docs.github.com/en/[email protected]/admin/release-notes#3.19.9
- https://docs.github.com/en/[email protected]/admin/release-notes#3.20.5
- https://docs.github.com/en/[email protected]/admin/release-notes#3.21.3
More GitHub vulnerabilities
- TI-2024-04632 An authentication bypass vulnerability was present in the GitHub Enterprise Server (GHES)… CVSS 4.0CRITICAL 10.0
- TI-2024-00181 Unsafe Reflection in Github Enterprise Server leading to Command Injection CVSS 3.1CRITICAL 9.8
- TI-2024-00466 Privilege Escalation by Code Injection in the Management Console in GitHub Enterprise Server CVSS 3.1HIGH 8.8
- TI-2022-08539 Integer overflow in table parsing extension leads to heap memory corruption CVSS 3.1CRITICAL 9.8
- TI-2026-34990 GitHub MCP Server: Nil Pointer Dereference DoS in completion/complete Handler CVSS 3.1HIGH 7.5
- TI-2026-32884 GitHub Copilot CLI: Nested Bare Repository Can Execute Arbitrary Commands via core.fsmonitor CVSS 4.0HIGH 8.5
Sources
- CVE-2026-15783 · CVE Program
- CVE-2026-15783 · NVD
- FIRST EPSS
- GHSA-qhvh-xjh2-7c8c · GitHub Advisory Database · CC BY 4.0
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