{"id":"CVE-2026-72693","state":"PUBLISHED","title":"Kbd: local privilege escalation in openvt via incorrect process owner verification allowing passwordless root login","description":"`openvt -u` is intended to identify the owner of the current VT and then execute `login` as that user from a privileged context. In the documented `kbrequest`/init usage, the ownership test in `authenticate_user()` relies on `stat(\"/proc/<pid>/fd/0\")`. `stat()` on `/proc/<pid>/fd/0` follows the symlink to the underlying TTY device node. As a result, `buf.st_uid` reflects the owner of the TTY node rather than the owner of the process holding the file descriptor. If the TTY owner returns to `root` or the getty owner after logout while an unprivileged process still has `fd 0` attached to that TTY, the check can incorrectly treat that process as belonging to the privileged console owner. Once that check succeeds, the `-u` path executes a passwordless login as the selected user. In the documented `kbrequest`/init deployment using `openvt -us`, this can result in passwordless `login -f root` on the spawned VT. This report establishes that privilege escalation path for that documented deployment; it does not claim equivalent reachability for deployments that do not use `openvt -u` from a privileged `kbrequest`/init path.","publishedAt":"2026-08-11T08:39:24.983Z","updatedAt":"2026-10-09T03:46:24.896Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"redhat"},"assigner":"redhat","products":["Red Hat Red Hat Enterprise Linux 10","Red Hat Red Hat Enterprise Linux 8","Red Hat Red Hat Enterprise Linux 9","Red Hat Red Hat OpenShift Container Platform 4.22","Red Hat Red Hat Hardened Images","Red Hat Red Hat Enterprise Linux 6","Red Hat Red Hat Enterprise Linux 7","Red Hat Red Hat OpenShift Container Platform 4"],"affected":[{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","packageName":"kbd","defaultStatus":"affected","versions":[{"version":"0:2.6.4-8.el10_2","status":"unaffected","lessThan":"*","versionType":"rpm"}],"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:10.2"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","packageName":"kbd","defaultStatus":"affected","versions":[{"version":"0:2.0.4-11.el8_10.1","status":"unaffected","lessThan":"*","versionType":"rpm"}],"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:8::baseos"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","packageName":"kbd","defaultStatus":"affected","versions":[{"version":"0:2.4.0-12.el9_8","status":"unaffected","lessThan":"*","versionType":"rpm"}],"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:9::baseos"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4.22","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"affected","versions":[{"version":"4.22.9.8.202608251819-0","status":"unaffected","lessThan":"*","versionType":"rpm"}],"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4.22::el9"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4.22","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"affected","versions":[{"version":"4.22.9.8.202609081748-0","status":"unaffected","lessThan":"*","versionType":"rpm"}],"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4.22::el9"]},{"vendor":"Red Hat","product":"Red Hat Hardened Images","packageName":"kbd-main","defaultStatus":"affected","versions":[{"version":"2.10.0-2.hum1","status":"unaffected","lessThan":"*","versionType":"rpm"}],"collectionURL":"https://catalog.redhat.com/software/containers/","cpes":["cpe:/a:redhat:hummingbird:1"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","packageName":"kbd","defaultStatus":"unknown","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","packageName":"kbd","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","packageName":"openshift/ose-rhel-coreos-8","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"]}],"references":["https://access.redhat.com/errata/RHSA-2026:41136","https://access.redhat.com/errata/RHSA-2026:57597","https://access.redhat.com/errata/RHSA-2026:57610","https://access.redhat.com/errata/RHSA-2026:60440","https://access.redhat.com/errata/RHSA-2026:66357","https://access.redhat.com/errata/RHSA-2026:78951","https://access.redhat.com/security/cve/CVE-2026-72693","https://bugzilla.redhat.com/show_bug.cgi?id=2462115"],"weaknesses":["CWE-284"],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/72xxx/CVE-2026-72693.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72693","state":"PUBLISHED","datePublished":"2026-08-11T08:39:24.983Z","dateUpdated":"2026-10-09T03:46:24.896Z","assignerShortName":"redhat","assignerOrgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","dateReserved":"2026-08-10T12:35:16.746Z"},"containers":{"cna":{"title":"Kbd: local privilege escalation in openvt via incorrect process owner verification allowing passwordless root login","descriptions":[{"lang":"en","value":"`openvt -u` is intended to identify the owner of the current VT and then execute `login` as that user from a privileged context. In the documented `kbrequest`/init usage, the ownership test in `authenticate_user()` relies on `stat(\"/proc/<pid>/fd/0\")`. `stat()` on `/proc/<pid>/fd/0` follows the symlink to the underlying TTY device node. As a result, `buf.st_uid` reflects the owner of the TTY node rather than the owner of the process holding the file descriptor. If the TTY owner returns to `root` or the getty owner after logout while an unprivileged process still has `fd 0` attached to that TTY, the check can incorrectly treat that process as belonging to the privileged console owner. Once that check succeeds, the `-u` path executes a passwordless login as the selected user. In the documented `kbrequest`/init deployment using `openvt -us`, this can result in passwordless `login -f root` on the spawned VT. This report establishes that privilege escalation path for that documented deployment; it does not claim equivalent reachability for deployments that do not use `openvt -u` from a privileged `kbrequest`/init path."}],"affected":[{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","packageName":"kbd","defaultStatus":"affected","versions":[{"version":"0:2.6.4-8.el10_2","status":"unaffected","lessThan":"*","versionType":"rpm"}],"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:10.2"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","packageName":"kbd","defaultStatus":"affected","versions":[{"version":"0:2.0.4-11.el8_10.1","status":"unaffected","lessThan":"*","versionType":"rpm"}],"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:8::baseos"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 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Instead, configure the keyboard request to initiate a standard authenticated login on the new virtual terminal, or disable the keyboard request binding entirely until a fix is available. Changes to `kbrequest` configurations may require a system restart or service reload to take effect."}],"timeline":[{"lang":"en","time":"2026-04-26T18:17:20.000Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-08-11T06:58:59.200Z","value":"Made public."}],"credits":[{"lang":"en","value":"This issue was discovered by Found by AISLE in partnership with Red Hat."}],"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-11T17:44:26.656399Z","id":"CVE-2026-72693","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-11T17:51:17.406Z"}}]}}}