Kbd: local privilege escalation in openvt via incorrect process owner verification allowing passwordless root login
CVSS v3
7.8
HIGH
EPSS Score
—
exploit probability
CISA KEV
No
known exploited
Exploitation
—
SSVC status
`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`
`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`
Active exploitation of CVE-2026-72693 has not been confirmed. The EPSS score is N/A%, indicating the estimated probability of exploitation in the next 30 days.
CVE-2026-72693 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string 3.1.
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Ranked by exploit probability (EPSS).