{"id":"CVE-2026-59851","title":"Libssh: libssh: authentication bypass via missing gssapi principal check","summary":"A flaw was found in libssh. On servers with GSSAPIKeyExchange enabled, the gssapi-keyex path does not verify whether the authenticated Kerberos principal is authorized for the requested local user, allowing authenticated clients to log i…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-863"],"vendor":"Red Hat","product":"libssh","affected":["libssh (all versions)","libssh-main (all versions)","libssh","libssh"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-07-22T18:14:50.808102Z"},"published":"2026-07-21","updated":"2026-11-04","sourceUpdated":"2026-11-04T23:09:45.220Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-59851","references":[{"url":"https://access.redhat.com/errata/RHSA-2026:42922","label":"RHSA-2026:42922"},{"url":"https://access.redhat.com/errata/RHSA-2026:55855","label":"RHSA-2026:55855"},{"url":"https://access.redhat.com/security/cve/CVE-2026-59851"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498184","label":"RHBZ#2498184"}],"tags":["cve.org"],"epss":0.00489,"epssPercentile":0.42359,"ingestedAt":"2026-11-05T21:36:00.672Z","slug":"CVE-2026-59851","body":"## Overview\n\nA flaw was found in libssh. On servers with GSSAPIKeyExchange enabled, the gssapi-keyex path does not verify whether the authenticated Kerberos principal is authorized for the requested local user, allowing authenticated clients to log in as arbitrary users.\n\n## Affected\n\n- `libssh (all versions)`\n- `libssh-main (all versions)`\n- `libssh`\n- `libssh`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n### Workarounds\n\nDisable GSSAPIKeyExchange.","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}