{"cve":"CVE-2026-6736","nvd":{"published":"2026-05-07T22:16:36.753","modified":"2026-10-26T20:10:00.160","status":"Analyzed","description":"An authentication bypass vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to create a local user account, bypassing the configured external identity provider. When external authentication was enabled, the signup endpoint did not properly enforce the authentication restriction, allowing account creation and session establishment without identity provider validation. The created account was limited to the default base permissions configured on the instance. Exploitation required network access to a GHES instance configured with an external authentication provider. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.2, 3.19.6, 3.18.9, 3.17.15, and 3.16.18.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","score":6.3},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","score":6.5},"cwes":["CWE-306"],"references":["https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.18","https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.15","https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.9","https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.6","https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.2"],"products":["github:enterprise_server"],"source":"nvd","synced_at":"2026-10-26T20:34:58.897451322+00:00"},"epss":{"cve":"CVE-2026-6736","score":0.00266,"percentile":0.18324,"date":"2026-10-26"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}