kbd-2.0.4-11.el8_10.1
エラータID: AXSA:2026-2029:02
The kbd packages provide tools for managing console behavior on a Linux system, including the keyboard, screen fonts, virtual terminals, and font files.
Security Fix(es):
* kbd: Local privilege escalation in openvt via incorrect process owner verification allowing passwordless root login (CVE-2026-72693)
For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
CVE-2026-72693
`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//fd/0")`. `stat()` on `/proc//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.
Update packages.
`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.
N/A
SRPMS
- kbd-2.0.4-11.el8_10.1.src.rpm
MD5: 56725a5e5a893fb2b2039d1a31e23e0b
SHA-256: 131372a592b99141c81b25be20860c04a655cfd6e6e2dbdad05dbc4524827859
Size: 1.03 MB
Asianux Server 8 for x86_64
- kbd-2.0.4-11.el8_10.1.x86_64.rpm
MD5: 7c067ce85ccf8cfe0352fe51824d7a22
SHA-256: cc5dbdd7306a6901bdfb4094c37388d4b9f1aa197b7b9bf8bada69c76fa67c43
Size: 388.19 kB - kbd-legacy-2.0.4-11.el8_10.1.noarch.rpm
MD5: 05a939691bae27e4ee770eecac51d5fc
SHA-256: be91a31baaf3a2b101018b92577b116cc4336cc2e7583d21cbc7719d15449885
Size: 480.42 kB - kbd-misc-2.0.4-11.el8_10.1.noarch.rpm
MD5: ed4802c88813038c36cc58cce62a06eb
SHA-256: 9819773f8614fecd09e00fd2f3317c33e1f398ff6255e459c694983458cc17e3
Size: 1.46 MB