# CVE-2026-72693: Kbd: local privilege escalation in openvt via incorrect process owner verification allowing passwordless root login CVE-2026-72693 is fixed in 5 products on 1 platform, first by DEBIAN-CVE-2026-72693, released August 11, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-72693 - Priority: High - CVSS: 7.8 (Important) - EPSS: 0.0015 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Aug 11, 2026 - Weakness: Improper Access Control - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-72693 ## 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//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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | kbd Debian 14 | 2.10.0-1 | [DEBIAN-CVE-2026-72693](https://patchblox.com/security/data/fix/linux/debian-cve-2026-72693.md) | Aug 11, 2026 | | Linux | kbd Fedora 43 | 2.8.0-4.fc43 | [FEDORA-2026-3A1183DF4C](https://patchblox.com/security/data/fix/linux/fedora-2026-3a1183df4c.md) | Aug 27, 2026 | | Linux | kbd RHEL 10 | 2.6.4-8.el10_2 | [RHSA-2026:57597](https://patchblox.com/security/data/fix/linux/rhsa-2026-57597.md) | Aug 21, 2026 | | Linux | kbd RHEL 8 | 0:2.0.4-11.el8_10.1 | [RHSA-2026:78951](https://patchblox.com/security/data/fix/linux/rhsa-2026-78951.md) | Oct 9, 2026 | | Linux | kbd RHEL 9 | 0:2.4.0-12.el9_8 | [RHSA-2026:57610](https://patchblox.com/security/data/fix/linux/rhsa-2026-57610.md) | Aug 21, 2026 | | Linux | kbd almalinux 10 | 2.6.4-8.el10_2 | [ALSA-2026:57597](https://patchblox.com/security/data/fix/linux/alsa-2026-57597.md) | Aug 20, 2026 | | Linux | kbd almalinux 8 | 2.0.4-11.el8_10.1 | [ALSA-2026:78951](https://patchblox.com/security/data/fix/linux/alsa-2026-78951.md) | Oct 8, 2026 | | Linux | kbd almalinux 9 | 2.4.0-12.el9_8 | [ALSA-2026:57610](https://patchblox.com/security/data/fix/linux/alsa-2026-57610.md) | Aug 20, 2026 | | Linux | kbd amzn 2023 | 2.4.0-2.amzn2023.0.4 | [ALAS2023-2026-2109](https://patchblox.com/security/data/fix/linux/alas2023-2026-2109.md) | Aug 31, 2026 | | Linux | kbd ol 10 | 0:2.6.4-8.el10_2 | [ELSA-2026-57597](https://patchblox.com/security/data/fix/linux/elsa-2026-57597.md) | Aug 20, 2026 | | Linux | kbd ol 8 | 0:2.0.4-11.el8_10.1 | [ELSA-2026-78951](https://patchblox.com/security/data/fix/linux/elsa-2026-78951.md) | Oct 8, 2026 | | Linux | kbd ol 9 | 0:2.4.0-12.el9_8 | [ELSA-2026-57610](https://patchblox.com/security/data/fix/linux/elsa-2026-57610.md) | Aug 20, 2026 | | Linux | kbd opensuse-leap 16.0 | 2.7.1-160000.3.1 | [OPENSUSE-SU-2026:21939-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21939-1.md) | Sep 23, 2026 | | Linux | kbd rocky 10 | 0:2.6.4-8.el10_2 | [RLSA-2026:57597](https://patchblox.com/security/data/fix/linux/rlsa-2026-57597.md) | Aug 21, 2026 | | Linux | kbd rocky 8 | 0:2.0.4-11.el8_10.1 | [RLSA-2026:78951](https://patchblox.com/security/data/fix/linux/rlsa-2026-78951.md) | Nov 7, 2026 | | Linux | kbd rocky 9 | 0:2.4.0-12.el9_8 | [RLSA-2026:57610](https://patchblox.com/security/data/fix/linux/rlsa-2026-57610.md) | Aug 21, 2026 | | Linux | kbd sles 15.6 | 2.4.0-150400.5.12.1 | [SUSE-SU-2026:4207-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4207-1.md) | Sep 16, 2026 | | Linux | kbd sles 15.7 | 2.4.0-150700.15.10.1 | [SUSE-SU-2026:4211-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4211-1.md) | Sep 16, 2026 | | Linux | kbd sles 16.0 | 2.7.1-160000.3.1 | [SUSE-SU-2026:23911-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23911-1.md) | Sep 23, 2026 | | Linux | kbd-debuginfo Fedora 43 | 2.8.0-4.fc43 | [FEDORA-2026-3A1183DF4C](https://patchblox.com/security/data/fix/linux/fedora-2026-3a1183df4c.md) | Aug 27, 2026 | | Linux | kbd-debuginfo amzn 2023 | 2.4.0-2.amzn2023.0.4 | [ALAS2023-2026-2109](https://patchblox.com/security/data/fix/linux/alas2023-2026-2109.md) | Aug 31, 2026 | | Linux | kbd-debugsource Fedora 43 | 2.8.0-4.fc43 | [FEDORA-2026-3A1183DF4C](https://patchblox.com/security/data/fix/linux/fedora-2026-3a1183df4c.md) | Aug 27, 2026 | | Linux | kbd-debugsource amzn 2023 | 2.4.0-2.amzn2023.0.4 | [ALAS2023-2026-2109](https://patchblox.com/security/data/fix/linux/alas2023-2026-2109.md) | Aug 31, 2026 | | Linux | kbd-legacy Fedora 43 | 2.8.0-4.fc43 | [FEDORA-2026-3A1183DF4C](https://patchblox.com/security/data/fix/linux/fedora-2026-3a1183df4c.md) | Aug 27, 2026 | | Linux | kbd-legacy RHEL 8 | 0:2.0.4-11.el8_10.1 | [RHSA-2026:78951](https://patchblox.com/security/data/fix/linux/rhsa-2026-78951.md) | Oct 9, 2026 | | Linux | kbd-legacy RHEL 9 | 0:2.4.0-12.el9_8 | [RHSA-2026:57610](https://patchblox.com/security/data/fix/linux/rhsa-2026-57610.md) | Aug 21, 2026 | | Linux | kbd-legacy almalinux 10 | 2.6.4-8.el10_2 | [ALSA-2026:57597](https://patchblox.com/security/data/fix/linux/alsa-2026-57597.md) | Aug 20, 2026 | | Linux | kbd-legacy almalinux 8 | 2.0.4-11.el8_10.1 | [ALSA-2026:78951](https://patchblox.com/security/data/fix/linux/alsa-2026-78951.md) | Oct 8, 2026 | | Linux | kbd-legacy almalinux 9 | 2.4.0-12.el9_8 | [ALSA-2026:57610](https://patchblox.com/security/data/fix/linux/alsa-2026-57610.md) | Aug 20, 2026 | | Linux | kbd-legacy amzn 2023 | 2.4.0-2.amzn2023.0.4 | [ALAS2023-2026-2109](https://patchblox.com/security/data/fix/linux/alas2023-2026-2109.md) | Aug 31, 2026 | | Linux | kbd-legacy ol 10 | 0:2.6.4-8.el10_2 | [ELSA-2026-57597](https://patchblox.com/security/data/fix/linux/elsa-2026-57597.md) | Aug 20, 2026 | | Linux | kbd-legacy ol 8 | 0:2.0.4-11.el8_10.1 | [ELSA-2026-78951](https://patchblox.com/security/data/fix/linux/elsa-2026-78951.md) | Oct 8, 2026 | | Linux | kbd-legacy ol 9 | 0:2.4.0-12.el9_8 | [ELSA-2026-57610](https://patchblox.com/security/data/fix/linux/elsa-2026-57610.md) | Aug 20, 2026 | | Linux | kbd-misc Fedora 43 | 2.8.0-4.fc43 | [FEDORA-2026-3A1183DF4C](https://patchblox.com/security/data/fix/linux/fedora-2026-3a1183df4c.md) | Aug 27, 2026 | | Linux | kbd-misc RHEL 8 | 0:2.0.4-11.el8_10.1 | [RHSA-2026:78951](https://patchblox.com/security/data/fix/linux/rhsa-2026-78951.md) | Oct 9, 2026 | | Linux | kbd-misc RHEL 9 | 0:2.4.0-12.el9_8 | [RHSA-2026:57610](https://patchblox.com/security/data/fix/linux/rhsa-2026-57610.md) | Aug 21, 2026 | | Linux | kbd-misc almalinux 10 | 2.6.4-8.el10_2 | [ALSA-2026:57597](https://patchblox.com/security/data/fix/linux/alsa-2026-57597.md) | Aug 20, 2026 | | Linux | kbd-misc almalinux 8 | 2.0.4-11.el8_10.1 | [ALSA-2026:78951](https://patchblox.com/security/data/fix/linux/alsa-2026-78951.md) | Oct 8, 2026 | | Linux | kbd-misc almalinux 9 | 2.4.0-12.el9_8 | [ALSA-2026:57610](https://patchblox.com/security/data/fix/linux/alsa-2026-57610.md) | Aug 20, 2026 | | Linux | kbd-misc amzn 2023 | 2.4.0-2.amzn2023.0.4 | [ALAS2023-2026-2109](https://patchblox.com/security/data/fix/linux/alas2023-2026-2109.md) | Aug 31, 2026 | | Linux | kbd-misc ol 10 | 0:2.6.4-8.el10_2 | [ELSA-2026-57597](https://patchblox.com/security/data/fix/linux/elsa-2026-57597.md) | Aug 20, 2026 | | Linux | kbd-misc ol 8 | 0:2.0.4-11.el8_10.1 | [ELSA-2026-78951](https://patchblox.com/security/data/fix/linux/elsa-2026-78951.md) | Oct 8, 2026 | | Linux | kbd-misc ol 9 | 0:2.4.0-12.el9_8 | [ELSA-2026-57610](https://patchblox.com/security/data/fix/linux/elsa-2026-57610.md) | Aug 20, 2026 | --- Data as of 2026-11-09T13:31:49Z UTC. 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