# CVE-2026-53612: util-linux mount hook_owner TOCTOU allows local privilege escalation

CVE-2026-53612 is fixed in 34 products on 1 platform, first by DEBIAN-CVE-2026-53612, released June 27, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-53612
- Priority: High
- CVSS: 8.0 (Moderate)
- EPSS: 0.0015
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 16, 2026
- Weakness: Time-of-check Time-of-use (TOCTOU) Race Condition
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-53612

## Description

util-linux is a random collection of Linux utilities. In util-linux 2.39 through 2.41.4 and 2.42 through 2.42.1, the SUID `mount` utility's `hook_owner.c` post-mount hook performs path-based `chmod()` and `lchown()` operations on a previously validated mount target. A local low-privileged user authorized by an `/etc/fstab` entry with `user` or `users` and an `X-mount.mode`, `X-mount.owner`, or `X-mount.group` option can use `renameat2(RENAME_EXCHANGE)` to race a writable ancestor of the target and redirect the privileged ownership or mode change to a root-owned path, potentially gaining root privileges. This issue is fixed in 2.41.5 and 2.42.2.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | bsdextrautils Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [bsdextrautils 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-bsdextrautils-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | bsdextrautils Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [bsdextrautils 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-bsdextrautils-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | bsdutils Ubuntu 24.04.5 LTS (noble) | 1:2.39.3-9ubuntu6.6 | [bsdutils 1:2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-bsdutils-1-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | bsdutils Ubuntu 26.04.1 LTS (resolute) | 1:2.41.3-3ubuntu2.2 | [bsdutils 1:2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-bsdutils-1-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | eject Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [eject 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-eject-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | eject Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [eject 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-eject-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | fdisk Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [fdisk 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-fdisk-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | fdisk Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [fdisk 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-fdisk-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | lastlog2 Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [lastlog2 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-lastlog2-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | libblkid almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libblkid ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libblkid-devel almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libblkid-devel ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libblkid1 Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [libblkid1 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libblkid1-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | libblkid1 Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [libblkid1 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libblkid1-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | libfdisk almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libfdisk ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libfdisk-devel almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libfdisk-devel ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libfdisk1 Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [libfdisk1 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libfdisk1-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | libfdisk1 Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [libfdisk1 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfdisk1-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | liblastlog2-2 Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [liblastlog2-2 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-liblastlog2-2-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | libmount almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libmount ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libmount-devel almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libmount-devel ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libmount1 Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [libmount1 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libmount1-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | libmount1 Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [libmount1 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libmount1-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | libpam-lastlog2 Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [libpam-lastlog2 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libpam-lastlog2-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | libsmartcols almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libsmartcols ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libsmartcols-devel almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libsmartcols-devel ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libsmartcols1 Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [libsmartcols1 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libsmartcols1-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | libsmartcols1 Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [libsmartcols1 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libsmartcols1-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | libuuid almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libuuid ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libuuid-devel almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libuuid-devel ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | libuuid1 Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [libuuid1 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libuuid1-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | libuuid1 Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [libuuid1 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libuuid1-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | login Ubuntu 26.04.1 LTS (resolute) | 1:4.16.0-2+really2.41.3-3ubuntu2.2 | [login 1:4.16.0-2+really2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-login-1-4.16.0-2-really2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | mount Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [mount 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-mount-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | mount Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [mount 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-mount-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | python-libmount opensuse-leap 16.0 | 2.41.1-160000.5.1 | [OPENSUSE-SU-2026:21905-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21905-1.md) | Sep 22, 2026 |
| Linux | python-libmount sles 16.0 | 2.41.1-160000.5.1 | [SUSE-SU-2026:23870-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23870-1.md) | Sep 22, 2026 |
| Linux | python3-libmount almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | python3-libmount ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | rfkill Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [rfkill 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-rfkill-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | rfkill Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [rfkill 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-rfkill-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | util-linux Debian 13.5 (trixie) | 2.41.5-0+deb13u1 | [DEBIAN-CVE-2026-53612](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53612.md) | Jun 27, 2026 |
| Linux | util-linux Debian 14 | 2.42.2-1 | [DEBIAN-CVE-2026-53612](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53612.md) | Jun 27, 2026 |
| Linux | util-linux RHEL 10 | 2.40.2-18.el10_2.20 | [RHSA-2026:93461](https://patchblox.com/security/data/fix/linux/rhsa-2026-93461.md) | Sep 2, 2026 |
| Linux | util-linux Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [util-linux 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-util-linux-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | util-linux Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [util-linux 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-util-linux-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | util-linux almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | util-linux ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | util-linux opensuse-leap 16.0 | 2.41.1-160000.5.1 | [OPENSUSE-SU-2026:21905-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21905-1.md) | Sep 22, 2026 |
| Linux | util-linux rocky 10 | 0:2.40.2-18.el10_2.20 | [RLSA-2026:93461](https://patchblox.com/security/data/fix/linux/rlsa-2026-93461.md) | Nov 7, 2026 |
| Linux | util-linux sles 15.6 | 2.39.3-150600.4.26.1 | [SUSE-SU-2026:3685-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3685-1.md) | Aug 21, 2026 |
| Linux | util-linux sles 15.7 | 2.40.4-150700.4.18.1 | [SUSE-SU-2026:3684-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3684-1.md) | Aug 21, 2026 |
| Linux | util-linux sles 16.0 | 2.41.1-160000.5.1 | [SUSE-SU-2026:23870-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23870-1.md) | Sep 22, 2026 |
| Linux | util-linux-core almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | util-linux-core ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |
| Linux | util-linux-extra Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [util-linux-extra 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-util-linux-extra-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | util-linux-extra Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [util-linux-extra 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-util-linux-extra-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | util-linux-locales Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [util-linux-locales 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-util-linux-locales-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | util-linux-locales Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [util-linux-locales 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-util-linux-locales-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | util-linux-systemd opensuse-leap 16.0 | 2.41.1-160000.5.1 | [OPENSUSE-SU-2026:21905-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21905-1.md) | Sep 22, 2026 |
| Linux | util-linux-systemd sles 15.6 | 2.39.3-150600.4.26.1 | [SUSE-SU-2026:3685-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3685-1.md) | Aug 21, 2026 |
| Linux | util-linux-systemd sles 15.7 | 2.40.4-150700.4.18.1 | [SUSE-SU-2026:3684-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3684-1.md) | Aug 21, 2026 |
| Linux | util-linux-systemd sles 16.0 | 2.41.1-160000.5.1 | [SUSE-SU-2026:23870-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23870-1.md) | Sep 22, 2026 |
| Linux | uuid-runtime Ubuntu 24.04.5 LTS (noble) | 2.39.3-9ubuntu6.6 | [uuid-runtime 2.39.3-9ubuntu6.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-uuid-runtime-2.39.3-9ubuntu6.6.md) | Jun 29, 2026 |
| Linux | uuid-runtime Ubuntu 26.04.1 LTS (resolute) | 2.41.3-3ubuntu2.2 | [uuid-runtime 2.41.3-3ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-uuid-runtime-2.41.3-3ubuntu2.2.md) | Jun 29, 2026 |
| Linux | uuidd almalinux 10 | 2.40.2-18.el10_2.20 | [ALSA-2026:93461](https://patchblox.com/security/data/fix/linux/alsa-2026-93461.md) | Nov 7, 2026 |
| Linux | uuidd ol 10 | 0:2.40.2-18.0.1.el10_2.20 | [ELSA-2026-93461](https://patchblox.com/security/data/fix/linux/elsa-2026-93461.md) | Nov 7, 2026 |

---

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