{"id":"CVE-2026-6736","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-6736","generatedAt":"2026-10-28T07:03:58.795Z","title":"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.","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.","published":"2026-05-07T22:16:37.000Z","lastModified":"2026-10-26T20:10:00.000Z","status":"Analyzed","sourceIdentifier":"product-cna@github.com","cvss":{"version":"4.0","score":6.3,"severity":"MEDIUM","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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-306"],"affected":["github/enterprise server"],"epss":{"score":0.00266,"percentile":0.18388,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.27%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.18","tags":["Release Notes","Vendor Advisory"],"source":"product-cna@github.com"},{"url":"https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.15","tags":["Release Notes","Vendor Advisory"],"source":"product-cna@github.com"},{"url":"https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.9","tags":["Release Notes","Vendor Advisory"],"source":"product-cna@github.com"},{"url":"https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.6","tags":["Release Notes","Vendor Advisory"],"source":"product-cna@github.com"},{"url":"https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.2","tags":["Release Notes","Vendor Advisory"],"source":"product-cna@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-6736","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}