CVE-2026-13595

A flaw was found in the libblkid library of util-linux. During nested partition probing, the BSD, Minix, Solaris x86, and UnixWare partition probers cache a raw pointer to a parent partition entry in a dynamically allocated array. When subsequent partition additions cause the array to be reallocated, this pointer becomes stale, leading to a heap use-after-free read. An attacker who can present a crafted block device image (for example, via USB insertion or a loop-mounted disk image) can trigger this flaw without user interaction, as libblkid is invoked automatically by udev/udisks as root on block-device hot-plug events. This could lead to limited information disclosure or denial of service.

A flaw was found in the libblkid library of util-linux. During nested partition probing, the BSD, Minix, Solaris x86, and UnixWare partition probers cache a raw pointer to a parent partition entry in a dynamically allocated array. When subsequent partition additions cause the array to be reallocated, this pointer becomes stale, leading to a heap use-after-free read. An attacker who can present a crafted block device image (for example, via USB insertion or a loop-mounted disk image) can trigger this flaw without user interaction, as libblkid is invoked automatically by udev/udisks as root on block-device hot-plug events. This could lead to limited information disclosure or denial of service.

The util-linux package contains a random collection of files that implements some low-level basic linux utilities.

Security Fix(es):

A flaw was found in the libblkid library of util-linux. During nested partition probing, the BSD, Minix, Solaris x86, and UnixWare partition probers cache a raw pointer to a parent partition entry in a dynamically allocated array. When subsequent partition additions cause the array to be reallocated, this pointer becomes stale, leading to a heap use-after-free read. An attacker who can present a crafted block device image (for example, via USB insertion or a loop-mounted disk image) can trigger this flaw without user interaction, as libblkid is invoked automatically by udev/udisks as root on block-device hot-plug events. This could lead to limited information disclosure or denial of service.(CVE-2026-13595)

The util-linux package contains a random collection of files that implements some low-level basic linux utilities.

Security Fix(es):

A flaw was found in the libblkid library of util-linux. During nested partition probing, the BSD, Minix, Solaris x86, and UnixWare partition probers cache a raw pointer to a parent partition entry in a dynamically allocated array. When subsequent partition additions cause the array to be reallocated, this pointer becomes stale, leading to a heap use-after-free read. An attacker who can present a crafted block device image (for example, via USB insertion or a loop-mounted disk image) can trigger this flaw without user interaction, as libblkid is invoked automatically by udev/udisks as root on block-device hot-plug events. This could lead to limited information disclosure or denial of service.(CVE-2026-13595)

The util-linux package contains a random collection of files that implements some low-level basic linux utilities.

Security Fix(es):

A flaw was found in the libblkid library of util-linux. During nested partition probing, the BSD, Minix, Solaris x86, and UnixWare partition probers cache a raw pointer to a parent partition entry in a dynamically allocated array. When subsequent partition additions cause the array to be reallocated, this pointer becomes stale, leading to a heap use-after-free read. An attacker who can present a crafted block device image (for example, via USB insertion or a loop-mounted disk image) can trigger this flaw without user interaction, as libblkid is invoked automatically by udev/udisks as root on block-device hot-plug events. This could lead to limited information disclosure or denial of service.(CVE-2026-13595)

The util-linux package contains a random collection of files that implements some low-level basic linux utilities.

Security Fix(es):

A flaw was found in the libblkid library of util-linux. During nested partition probing, the BSD, Minix, Solaris x86, and UnixWare partition probers cache a raw pointer to a parent partition entry in a dynamically allocated array. When subsequent partition additions cause the array to be reallocated, this pointer becomes stale, leading to a heap use-after-free read. An attacker who can present a crafted block device image (for example, via USB insertion or a loop-mounted disk image) can trigger this flaw without user interaction, as libblkid is invoked automatically by udev/udisks as root on block-device hot-plug events. This could lead to limited information disclosure or denial of service.(CVE-2026-13595)

The util-linux package contains a random collection of files that implements some low-level basic linux utilities.

Security Fix(es):

A flaw was found in the libblkid library of util-linux. During nested partition probing, the BSD, Minix, Solaris x86, and UnixWare partition probers cache a raw pointer to a parent partition entry in a dynamically allocated array. When subsequent partition additions cause the array to be reallocated, this pointer becomes stale, leading to a heap use-after-free read. An attacker who can present a crafted block device image (for example, via USB insertion or a loop-mounted disk image) can trigger this flaw without user interaction, as libblkid is invoked automatically by udev/udisks as root on block-device hot-plug events. This could lead to limited information disclosure or denial of service.(CVE-2026-13595)

The util-linux packages contain a large variety of low-level system utilities that are necessary for a Linux system to function. Among others, these include the fdisk configuration tool and the login program.

Security Fix(es):

• util-linux: TOCTOU in the mount program when setting up loop devices (CVE-2026-27456)

• util-linux: util-linux: heap use-after-free in libblkid nested partition probing (CVE-2026-13595)

• util-linux: TOCTOU in the mount program via ancestor directory swap on target path (CVE-2026-53613)

• util-linux: util-linux: TOCTOU in the mount program when applying post-mount ownership/mode changes (CVE-2026-53612)

• util-linux: util-linux: SUID mount(8) allows nosuid/noexec bypass via LIBMOUNT_FORCE_MOUNT2 (CVE-2026-53614)

• util-linux: util-linux: failed external mount helper still runs privileged X-mount post-hooks (CVE-2026-76642)

• util-linux: util-linux: nsenter --join-cgroup leaks root cgroup migration authority (CVE-2026-78408)

• util-linux: util-linux: restricted bind mounts do not pin the source, allowing X-mount.owner/group/mode redirection (CVE-2026-78410)

• util-linux: util-linux: Partition metadata compromise via integer overflow in DOS partition parser (CVE-2026-53615)

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.

A flaw was found in the libblkid library of util-linux. During nested partition probing, the BSD, Minix, Solaris x86, and UnixWare partition probers cache a raw pointer to a parent partition entry in a dynamically allocated array. When subsequent partition additions cause the array to be reallocated, this pointer becomes stale, leading to a heap use-after-free read. An attacker who can present a crafted block device image (for example, via USB insertion or a loop-mounted disk image) can trigger this flaw without user interaction, as libblkid is invoked automatically by udev/udisks as root on block-device hot-plug events. This could lead to limited information disclosure or denial of service.

The util-linux packages contain a large variety of low-level system utilities that are necessary for a Linux system to function. Among others, these include the fdisk configuration tool and the login program.

Security Fix(es):

• util-linux: TOCTOU in the mount program when setting up loop devices (CVE-2026-27456)
• util-linux: util-linux: heap use-after-free in libblkid nested partition probing (CVE-2026-13595)
• util-linux: TOCTOU in the mount program via ancestor directory swap on target path (CVE-2026-53613)
• util-linux: util-linux: TOCTOU in the mount program when applying post-mount ownership/mode changes (CVE-2026-53612)
• util-linux: util-linux: SUID mount(8) allows nosuid/noexec bypass via LIBMOUNT_FORCE_MOUNT2 (CVE-2026-53614)
• util-linux: util-linux: failed external mount helper still runs privileged X-mount post-hooks (CVE-2026-76642)
• util-linux: util-linux: nsenter --join-cgroup leaks root cgroup migration authority (CVE-2026-78408)
• util-linux: util-linux: restricted bind mounts do not pin the source, allowing X-mount.owner/group/mode redirection (CVE-2026-78410)
• util-linux: util-linux: Partition metadata compromise via integer overflow in DOS partition parser (CVE-2026-53615)

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.

A flaw was found in the libblkid library of util-linux. During nested partition probing, the BSD, Minix, Solaris x86, and UnixWare partition probers cache a raw pointer to a parent partition entry in a dynamically allocated array. When subsequent partition additions cause the array to be reallocated, this pointer becomes stale, leading to a heap use-after-free read. An attacker who can present a crafted block device image (for example, via USB insertion or a loop-mounted disk image) can trigger this flaw without user interaction, as libblkid is invoked automatically by udev/udisks as root on block-device hot-plug events. This could lead to limited information disclosure or denial of service.

• CVE-2026-13595: libblkid: fix use-after-free in nested partition probing by switching parts pool from array-of-structs to array-of-pointers so blkid_partition addresses stay stable across pool growth

• CVE-2026-13595: libblkid: fix heap use-after-free read in nested partition probing where the BSD, Minix, Solaris x86 and UnixWare probers cached a pointer into the partition array that was invalidated when adding further partitions reallocated it; store partitions as an array of individually allocated pointers so partition pointers stay stable across reallocation

These are all security issues fixed in the libblkid-devel-2.42.2-1.1 package on the GA media of openSUSE Tumbleweed.

This update for util-linux fixes the following issues:

• CVE-2026-13595: heap use-after-free in libblkid nested partition probing (bsc#1269583).
• CVE-2026-27456: TOCTOU in the mount program when setting up loop devices (bsc#1261606).
• CVE-2026-53612: local privilege escalation via TOCTOU in mount(8) hook_owner.c chmod/chown (bsc#1268886).
• CVE-2026-53613: local privilege escalation via TOCTOU in mount(8) - Target Path Redirection (bsc#1268886).
• CVE-2026-53614: local privilege escalation via LIBMOUNT_FORCE_MOUNT2 Environment Variable - nosuid/noexec Bypass in SUID mount(8) (bsc#1268886).
• CVE-2026-76642: failed external mount helper triggers privileged X-mount post-hooks, which enables local privilege escalation (bsc#1278349).
• CVE-2026-78408: nsenter --join-cgroup leaks root cgroup migration authority, which allows for migration or termination of root processes (bsc#1278348).
• CVE-2026-78410: restricted bind mounts do not pin the source, which allows for X-mount.owner/group/mode redirection (bsc#1278347).

Changes for util-linux:

• lib/fileutils: add ul_openat_resolve() openat2 wrapper (bsc#1275441)
• lib/fileutils: fix RESOLVE_NO_SYMLINKS fallback value
• lib/fileutils: fix unused parameter warnings without SYS_openat2
• libmount: add missing fileutils.h include to hook_idmap.c
• libmount: add mnt_open_tree() helper for safe tree opening
• libmount: pin source path with openat2() for restricted users (bsc#1275441, bsc#1278347, CVE-2026-78410)
• libmount: restrict source path canonicalization for non-root users (bsc#1275441, bsc#1278347, CVE-2026-78410)
• libmount: skip post-mount hooks after failed mount helper (bsc#1275441, bsc#1278349, CVE-2026-76642)
• libmount: use USE_LIBMOUNT_MOUNTFD_SUPPORT for idmap hook
• nsenter: close cgroup.procs fd after join to prevent authority leak (bsc#1275441, bsc#1278348, CVE-2026-78408)
• nsenter, unshare: add O_CLOEXEC to all open() calls (bsc#1275441, bsc#1278348, CVE-2026-78408)
• wall, write: sanitize hostname in banner header (bsc#1275441)
• Add missing function. (bsc#1275441)
• ipcutils: Prevent using uninitialized variable (bsc#1268886)
• BREAKING CHANGE: Paths must always be canonicalized for unprivileged users to ensure safe target resolution. X-mount.nocanonicalize is ignored for them.
• INCOMAPTIBLE CHANGE (linux < 6.15): X-mount.subdir: The safe detached subdirectory is no more supported for unprivileged users for safety reasons.
• liblastlog2: Wait on busy SQLite connections (bsc#1268886).
• libmount: Fix subvolid buffer overflow in get_btrfs_fs_root (bsc#1268886).
• libblkid: Fix use-after-free in nested partition probing (bsc#1269583, bsc#1268886, CVE-2026-13595)
• libmount: fix SUID bypass via LIBMOUNT_FORCE_MOUNT2 and legacy mount path (bsc#1268886, CVE-2026-53614, GHSA-67r7-8m5w-22wx).
• fileutils: add ul_open_no_symlinks() needed by other patches (bsc#1268886).
• libmount: add fd_target to context for TOCTOU race condition prevention (bsc#1268886, CVE-2026-53613, GHSA-8gj5-72r3-428g).
• libmount: ignore X-mount.nocanonicalize for restricted users
• libmount: use fd-based fchownat/chmod in hook_owner (bsc#1268886, CVE-2026-53612, GHSA-g8wm-75wr-g2vh).
• libmount: restrict X-mount.subdir for non-root (bsc#1268886).
• libmount: use fd_target in hook_idmap for move_mount()
• libmount: add mount ID verification and man page TOCTOU note
• loopdev: use openat2(RESOLVE_NO_SYMLINKS) for backing file (bsc#1268886#c2, bsc#1261606).
• Ignore pam-config error that prevents update failure if common* pam configuration is not symlink to common-*-pc (bsc#1270219).

Root has patched CVE-2026-13595 in the util-linux package for Root:Debian:11. Multiple fixed versions available.

Root has patched CVE-2026-13595 in the util-linux package for Root:Debian:12. Multiple fixed versions available.

Root has patched CVE-2026-13595 in the util-linux package for Root:Debian:13. Multiple fixed versions available.

This update for util-linux fixes the following issues:

• CVE-2026-13595: heap use-after-free read in libblkid nested partition probing (bsc#1269583).
• CVE-2026-27456: TOCTOU race condition in the mount program when setting up loop devices (bsc#1261606).
• Several security issues in releases prior to v2.42.2 and v2.41.5 (bsc#1268886).

This update for util-linux fixes the following issues:

Security issues fixed:

• CVE-2026-13595: heap use-after-free read in libblkid nested partition probing (bsc#1269583).
• CVE-2026-27456: TOCTOU race condition in the mount program when setting up loop devices (bsc#1261606).
• Several security issues in releases prior to v2.42.2 and v2.41.5 (bsc#1268886).

Other updates and bugfixes:

• Ignore pam-config error that prevents update failure if common* pam configuration is not symlink to common-*-pc (bsc#1270219).

This update for util-linux fixes the following issues:

• CVE-2026-13595: heap use-after-free in libblkid nested partition probing (bsc#1269583).
• CVE-2026-27456: TOCTOU in the mount program when setting up loop devices (bsc#1261606).
• CVE-2026-53612: local privilege escalation via TOCTOU in mount(8) hook_owner.c chmod/chown (bsc#1268886).
• CVE-2026-53613: local privilege escalation via TOCTOU in mount(8) - Target Path Redirection (bsc#1268886).
• CVE-2026-53614: local privilege escalation via LIBMOUNT_FORCE_MOUNT2 Environment Variable - nosuid/noexec Bypass in SUID mount(8) (bsc#1268886).
• CVE-2026-76642: failed external mount helper triggers privileged X-mount post-hooks, which enables local privilege escalation (bsc#1278349).
• CVE-2026-78408: nsenter --join-cgroup leaks root cgroup migration authority, which allows for migration or termination of root processes (bsc#1278348).
• CVE-2026-78410: restricted bind mounts do not pin the source, which allows for X-mount.owner/group/mode redirection (bsc#1278347).

Changes for util-linux:

• lib/fileutils: add ul_openat_resolve() openat2 wrapper (bsc#1275441)
• lib/fileutils: fix RESOLVE_NO_SYMLINKS fallback value
• lib/fileutils: fix unused parameter warnings without SYS_openat2
• libmount: add missing fileutils.h include to hook_idmap.c
• libmount: add mnt_open_tree() helper for safe tree opening
• libmount: pin source path with openat2() for restricted users (bsc#1275441, bsc#1278347, CVE-2026-78410)
• libmount: restrict source path canonicalization for non-root users (bsc#1275441, bsc#1278347, CVE-2026-78410)
• libmount: skip post-mount hooks after failed mount helper (bsc#1275441, bsc#1278349, CVE-2026-76642)
• libmount: use USE_LIBMOUNT_MOUNTFD_SUPPORT for idmap hook
• nsenter: close cgroup.procs fd after join to prevent authority leak (bsc#1275441, bsc#1278348, CVE-2026-78408)
• nsenter, unshare: add O_CLOEXEC to all open() calls (bsc#1275441, bsc#1278348, CVE-2026-78408)
• wall, write: sanitize hostname in banner header (bsc#1275441)
• Add missing function. (bsc#1275441)
• ipcutils: Prevent using uninitialized variable (bsc#1268886)
• BREAKING CHANGE: Paths must always be canonicalized for unprivileged users to ensure safe target resolution. X-mount.nocanonicalize is ignored for them.
• INCOMAPTIBLE CHANGE (linux < 6.15): X-mount.subdir: The safe detached subdirectory is no more supported for unprivileged users for safety reasons.
• liblastlog2: Wait on busy SQLite connections (bsc#1268886).
• libmount: Fix subvolid buffer overflow in get_btrfs_fs_root (bsc#1268886).
• libblkid: Fix use-after-free in nested partition probing (bsc#1269583, bsc#1268886, CVE-2026-13595)
• libmount: fix SUID bypass via LIBMOUNT_FORCE_MOUNT2 and legacy mount path (bsc#1268886, CVE-2026-53614, GHSA-67r7-8m5w-22wx).
• fileutils: add ul_open_no_symlinks() needed by other patches (bsc#1268886).
• libmount: add fd_target to context for TOCTOU race condition prevention (bsc#1268886, CVE-2026-53613, GHSA-8gj5-72r3-428g).
• libmount: ignore X-mount.nocanonicalize for restricted users
• libmount: use fd-based fchownat/chmod in hook_owner (bsc#1268886, CVE-2026-53612, GHSA-g8wm-75wr-g2vh).
• libmount: restrict X-mount.subdir for non-root (bsc#1268886).
• libmount: use fd_target in hook_idmap for move_mount()
• libmount: add mount ID verification and man page TOCTOU note
• loopdev: use openat2(RESOLVE_NO_SYMLINKS) for backing file (bsc#1268886#c2, bsc#1261606).
• Ignore pam-config error that prevents update failure if common* pam configuration is not symlink to common-*-pc (bsc#1270219).

This update for util-linux fixes the following issues:

• CVE-2026-13595: heap use-after-free in libblkid nested partition probing (bsc#1269583).
• CVE-2026-27456: TOCTOU in the mount program when setting up loop devices (bsc#1261606).
• CVE-2026-53612: local privilege escalation via TOCTOU in mount(8) hook_owner.c chmod/chown (bsc#1268886).
• CVE-2026-53613: local privilege escalation via TOCTOU in mount(8) - Target Path Redirection (bsc#1268886).
• CVE-2026-53614: local privilege escalation via LIBMOUNT_FORCE_MOUNT2 Environment Variable - nosuid/noexec Bypass in SUID mount(8) (bsc#1268886).
• CVE-2026-76642: failed external mount helper triggers privileged X-mount post-hooks, which enables local privilege escalation (bsc#1278349).
• CVE-2026-78408: nsenter --join-cgroup leaks root cgroup migration authority, which allows for migration or termination of root processes (bsc#1278348).
• CVE-2026-78410: restricted bind mounts do not pin the source, which allows for X-mount.owner/group/mode redirection (bsc#1278347).

Changes for util-linux:

• lib/fileutils: add ul_openat_resolve() openat2 wrapper (bsc#1275441)
• lib/fileutils: fix RESOLVE_NO_SYMLINKS fallback value
• lib/fileutils: fix unused parameter warnings without SYS_openat2
• libmount: add missing fileutils.h include to hook_idmap.c
• libmount: add mnt_open_tree() helper for safe tree opening
• libmount: pin source path with openat2() for restricted users (bsc#1275441, bsc#1278347, CVE-2026-78410)
• libmount: restrict source path canonicalization for non-root users (bsc#1275441, bsc#1278347, CVE-2026-78410)
• libmount: skip post-mount hooks after failed mount helper (bsc#1275441, bsc#1278349, CVE-2026-76642)
• libmount: use USE_LIBMOUNT_MOUNTFD_SUPPORT for idmap hook
• nsenter: close cgroup.procs fd after join to prevent authority leak (bsc#1275441, bsc#1278348, CVE-2026-78408)
• nsenter, unshare: add O_CLOEXEC to all open() calls (bsc#1275441, bsc#1278348, CVE-2026-78408)
• wall, write: sanitize hostname in banner header (bsc#1275441)
• Add missing function. (bsc#1275441)
• ipcutils: Prevent using uninitialized variable (bsc#1268886)
• BREAKING CHANGE: Paths must always be canonicalized for unprivileged users to ensure safe target resolution. X-mount.nocanonicalize is ignored for them.
• INCOMAPTIBLE CHANGE (linux < 6.15): X-mount.subdir: The safe detached subdirectory is no more supported for unprivileged users for safety reasons.
• liblastlog2: Wait on busy SQLite connections (bsc#1268886).
• libmount: Fix subvolid buffer overflow in get_btrfs_fs_root (bsc#1268886).
• libblkid: Fix use-after-free in nested partition probing (bsc#1269583, bsc#1268886, CVE-2026-13595)
• libmount: fix SUID bypass via LIBMOUNT_FORCE_MOUNT2 and legacy mount path (bsc#1268886, CVE-2026-53614, GHSA-67r7-8m5w-22wx).
• fileutils: add ul_open_no_symlinks() needed by other patches (bsc#1268886).
• libmount: add fd_target to context for TOCTOU race condition prevention (bsc#1268886, CVE-2026-53613, GHSA-8gj5-72r3-428g).
• libmount: ignore X-mount.nocanonicalize for restricted users
• libmount: use fd-based fchownat/chmod in hook_owner (bsc#1268886, CVE-2026-53612, GHSA-g8wm-75wr-g2vh).
• libmount: restrict X-mount.subdir for non-root (bsc#1268886).
• libmount: use fd_target in hook_idmap for move_mount()
• libmount: add mount ID verification and man page TOCTOU note
• loopdev: use openat2(RESOLVE_NO_SYMLINKS) for backing file (bsc#1268886#c2, bsc#1261606).
• Ignore pam-config error that prevents update failure if common* pam configuration is not symlink to common-*-pc (bsc#1270219).

This update for util-linux fixes the following issues:

• CVE-2026-13595: heap use-after-free in libblkid nested partition probing (bsc#1269583).
• CVE-2026-27456: TOCTOU in the mount program when setting up loop devices (bsc#1261606).
• CVE-2026-53612: local privilege escalation via TOCTOU in mount(8) hook_owner.c chmod/chown (bsc#1268886).
• CVE-2026-53613: local privilege escalation via TOCTOU in mount(8) - Target Path Redirection (bsc#1268886).
• CVE-2026-53614: local privilege escalation via LIBMOUNT_FORCE_MOUNT2 Environment Variable - nosuid/noexec Bypass in SUID mount(8) (bsc#1268886).
• CVE-2026-76642: failed external mount helper triggers privileged X-mount post-hooks, which enables local privilege escalation (bsc#1278349).
• CVE-2026-78408: nsenter --join-cgroup leaks root cgroup migration authority, which allows for migration or termination of root processes (bsc#1278348).
• CVE-2026-78410: restricted bind mounts do not pin the source, which allows for X-mount.owner/group/mode redirection (bsc#1278347).

Changes for util-linux:

• lib/fileutils: add ul_openat_resolve() openat2 wrapper (bsc#1275441)
• lib/fileutils: fix RESOLVE_NO_SYMLINKS fallback value
• lib/fileutils: fix unused parameter warnings without SYS_openat2
• libmount: add missing fileutils.h include to hook_idmap.c
• libmount: add mnt_open_tree() helper for safe tree opening
• libmount: pin source path with openat2() for restricted users (bsc#1275441, bsc#1278347, CVE-2026-78410)
• libmount: restrict source path canonicalization for non-root users (bsc#1275441, bsc#1278347, CVE-2026-78410)
• libmount: skip post-mount hooks after failed mount helper (bsc#1275441, bsc#1278349, CVE-2026-76642)
• libmount: use USE_LIBMOUNT_MOUNTFD_SUPPORT for idmap hook
• nsenter: close cgroup.procs fd after join to prevent authority leak (bsc#1275441, bsc#1278348, CVE-2026-78408)
• nsenter, unshare: add O_CLOEXEC to all open() calls (bsc#1275441, bsc#1278348, CVE-2026-78408)
• wall, write: sanitize hostname in banner header (bsc#1275441)
• Add missing function. (bsc#1275441)
• ipcutils: Prevent using uninitialized variable (bsc#1268886)
• BREAKING CHANGE: Paths must always be canonicalized for unprivileged users to ensure safe target resolution. X-mount.nocanonicalize is ignored for them.
• INCOMAPTIBLE CHANGE (linux < 6.15): X-mount.subdir: The safe detached subdirectory is no more supported for unprivileged users for safety reasons.
• liblastlog2: Wait on busy SQLite connections (bsc#1268886).
• libmount: Fix subvolid buffer overflow in get_btrfs_fs_root (bsc#1268886).
• libblkid: Fix use-after-free in nested partition probing (bsc#1269583, bsc#1268886, CVE-2026-13595)
• libmount: fix SUID bypass via LIBMOUNT_FORCE_MOUNT2 and legacy mount path (bsc#1268886, CVE-2026-53614, GHSA-67r7-8m5w-22wx).
• fileutils: add ul_open_no_symlinks() needed by other patches (bsc#1268886).
• libmount: add fd_target to context for TOCTOU race condition prevention (bsc#1268886, CVE-2026-53613, GHSA-8gj5-72r3-428g).
• libmount: ignore X-mount.nocanonicalize for restricted users
• libmount: use fd-based fchownat/chmod in hook_owner (bsc#1268886, CVE-2026-53612, GHSA-g8wm-75wr-g2vh).
• libmount: restrict X-mount.subdir for non-root (bsc#1268886).
• libmount: use fd_target in hook_idmap for move_mount()
• libmount: add mount ID verification and man page TOCTOU note
• loopdev: use openat2(RESOLVE_NO_SYMLINKS) for backing file (bsc#1268886#c2, bsc#1261606).
• Ignore pam-config error that prevents update failure if common* pam configuration is not symlink to common-*-pc (bsc#1270219).

This update for util-linux fixes the following issues:

• CVE-2026-13595: heap use-after-free read in libblkid nested partition probing (bsc#1269583).
• CVE-2026-27456: TOCTOU race condition in the mount program when setting up loop devices (bsc#1261606).
• Several security issues in releases prior to v2.42.2 and v2.41.5 (bsc#1268886).

This update for util-linux fixes the following issues:

• CVE-2026-13595: heap use-after-free read in libblkid nested partition probing (bsc#1269583).
• CVE-2026-27456: TOCTOU race condition in the mount program when setting up loop devices (bsc#1261606).
• Several security issues in releases prior to v2.42.2 and v2.41.5 (bsc#1268886).

This update for util-linux fixes the following issues:

• CVE-2026-13595: heap use-after-free read in libblkid nested partition probing (bsc#1269583).
• CVE-2026-27456: TOCTOU race condition in the mount program when setting up loop devices (bsc#1261606).
• Several security issues in releases prior to v2.42.2 and v2.41.5 (bsc#1268886).

This update for util-linux fixes the following issues:

• CVE-2026-13595: heap use-after-free read in libblkid nested partition probing (bsc#1269583).
• CVE-2026-27456: TOCTOU race condition in the mount program when setting up loop devices (bsc#1261606).
• Several security issues in releases prior to v2.42.2 and v2.41.5 (bsc#1268886).

This update for util-linux fixes the following issues:

• CVE-2026-13595: heap use-after-free in libblkid nested partition probing (bsc#1269583).
• CVE-2026-27456: TOCTOU in the mount program when setting up loop devices (bsc#1261606).
• CVE-2026-53613: Local Privilege Escalation via TOCTOU in mount(8) — Target Path Redirection (bsc#1268886)

It was discovered that libblkid in util-linux had a heap use-after-free vulnerability during nested partition probing. An attacker who could present a crafted block device image could possibly use this issue to obtain sensitive information or cause a denial of service. (CVE-2026-13595)

It was discovered that the mount utility in util-linux had a time-of-check- time-of-use vulnerability when setting up loop devices. A local attacker could possibly use this issue to obtain unauthorized read access to root- protected files and block devices. (CVE-2026-27456)

It was discovered that the login utility in util-linux improperly canonicalized hostnames when invoked with the -h option. A remote attacker could possibly use this issue to bypass host-based access control rules. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-3184)

It was discovered that libmount in util-linux had a time-of-check-time-of- use vulnerability in its ownership hook. A local attacker could possibly use this issue to gain elevated privileges. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-53612)

It was discovered that libmount in util-linux had a time-of-check-time-of- use vulnerability that allowed target path redirection during mount operations. A local attacker could possibly use this issue to gain elevated privileges. (CVE-2026-53613)

It was discovered that libmount in util-linux improperly handled the LIBMOUNT_FORCE_MOUNT2 environment variable in the SUID mount utility. A local attacker could possibly use this issue to bypass nosuid and noexec mount options and gain elevated privileges. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-53614)

It was discovered that libblkid in util-linux had an integer overflow vulnerability when parsing DOS partition tables. An attacker who could present a crafted block device image could possibly use this issue to cause a denial of service. (CVE-2026-53615)