high · CVSS 7.8

CVE-2026-72693

Kbd: local privilege escalation in openvt via incorrect process owner verification allowing passwordless root login

Published 11 Aug 2026 · Source updated 5 Nov 2026 · Retrieved 2026-11-05 22:56 UTC

Monitor this CVE ↗Full CVE monitoring on Pro and Business

What happened?

`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.

Description supplied by CVE Program. Formatting is simplified; follow the original advisory for full details.

Affected software and versions

Source-provided software and version information
Software	Version information	Fixed version
kbdRed Hat	unaffected: 0:2.6.4-8.el10_2 to < *	See vendor advisory
kbdRed Hat	unaffected: 0:2.0.4-11.el8_10.1 to < *	See vendor advisory
kbdRed Hat	unaffected: 0:2.4.0-12.el9_8 to < *	See vendor advisory
openshift/ose-rhel-coreos-9Red Hat	unaffected: 4.22.9.8.202608251819-0 to < *	See vendor advisory
openshift/ose-rhel-coreos-9Red Hat	unaffected: 4.22.9.8.202609081748-0 to < *	See vendor advisory
kbd-mainRed Hat	unaffected: 2.10.0-2.hum1 to < *	See vendor advisory
kbdRed Hat	Default status: unknown	See vendor advisory
kbdRed Hat	Default status: affected	See vendor advisory
openshift/ose-rhel-coreos-8Red Hat	Default status: affected	See vendor advisory
openshift/ose-rhel-coreos-9Red Hat	Default status: affected	See vendor advisory

Version information comes from the source record and can include unaffected products and exceptions. Distribution packages may contain backported fixes: an older upstream version alone does not prove a server is affected.

Is it being exploited?

This CVE was not listed in the CISA catalogue at our last retrieval. This does not establish that exploitation is absent.

CISA data retrieved 2026-11-06 16:38 UTC. Check CISA ↗

How to respond

Confirm the product, installed package version, and any configuration requirements in the vendor advisory.
Follow the vendor’s remediation or workaround guidance in the references below. Structured fixed-version data is unavailable here; the publisher’s description may include a fix or workaround.
Restart affected services if required, then verify the running version. Known exploitation may warrant investigation as well as patching.

Sources and remediation references

This public advisory does not determine whether a particular server is affected. Records are refreshed as sources change; verify urgent decisions against the original advisory.

← Browse the public CVE feed