# CVE-2026-5845: Improper authorization fallback allows scoped user-to-server token installation escape in GitHub Enterprise Server

> CVE-2026-5845: Improper authorization fallback allows scoped user-to-server token installation escape in GitHub Enterprise Server. CVSS 9.6 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-5845
Last updated: 2026-06-17T10:59:44Z

- Published: 2026-04-21 22:42 UTC · Updated: 2026-06-17 10:59 UTC · Assigner: GitHub\_P
- CVSS: 9.6 (CVSS 3.1) · Severity: Critical · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
- EPSS: 0.29%, 21th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-639

## Description

An improper authorization vulnerability in scoped user-to-server (ghu\_) token authorization in GitHub Enterprise Server allows an authenticated attacker to access private repositories outside the intended installation scope, which can include write operations, via an authorization fallback that treated a revoked/deleted installation as a global installation context, which could be chained with token revocation timing and SSH push attribution to obtain and reuse a victim-scoped token. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.1, 3.19.5, 3.18.8, 3.17.14, 3.16.17, 3.15.21, and 3.14.26. This vulnerability was reported via the GitHub Bug Bounty program.

## Affected vendors and products

- GitHub: Enterprise Server

## Tracked companies

- [GitHub](https://rewindex.com/company/github.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-5845)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-5845)
- [https://docs.github.com/en/enterprise-server@3.14/admin/release-notes\#3.14.26](https://docs.github.com/en/enterprise-server@3.14/admin/release-notes#3.14.26)
- [https://docs.github.com/en/enterprise-server@3.15/admin/release-notes\#3.15.21](https://docs.github.com/en/enterprise-server@3.15/admin/release-notes#3.15.21)
- [https://docs.github.com/en/enterprise-server@3.16/admin/release-notes\#3.16.17](https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.17)
- [https://docs.github.com/en/enterprise-server@3.17/admin/release-notes\#3.17.14](https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.14)
- [https://docs.github.com/en/enterprise-server@3.18/admin/release-notes\#3.18.8](https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.8)
- [https://docs.github.com/en/enterprise-server@3.19/admin/release-notes\#3.19.5](https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.5)
- [https://docs.github.com/en/enterprise-server@3.20/admin/release-notes\#3.20.1](https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.1)

---

_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


---
Canonical: https://rewindex.com/cve/CVE-2026-5845 · Markdown: https://rewindex.com/cve/CVE-2026-5845.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-5845 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:12:57.805Z