CVE-2026-76642 util-linux libmount Privilege Escalation via Failed Mount Helper

util-linux versions through 2.41.5 and 2.42.2 fail to check mount helper exit status before running post-mount hooks, allowing unprivileged users to execute privileged operations on pre-existing filesystems. Attackers can exploit X-mount.idmap or X-mount.owner hooks to clone filesystems with...

CVE-2026-76642

util-linux (libmount component) versions through 2.41.5 and 2.42.2 fail to check the exit status of an external mount helper before executing privileged post-mount hooks. A local unprivileged user with an /etc/fstab entry using the user option combined with X-mount.idmap or X-mount.owner/group/mo...

CVE-2026-76642

util-linux versions through 2.41.5 and 2.42.2 fail to check mount helper exit status before running post-mount hooks, allowing unprivileged users to execute privileged operations on pre-existing filesystems. Attackers can exploit X-mount.idmap or X-mount.owner hooks to clone filesystems with...

PT-2026-90896

util-linux versions through 2.41.5 and 2.42.2 fail to check mount helper exit status before running post-mount hooks, allowing unprivileged users to execute privileged operations on pre-existing filesystems. Attackers can exploit X-mount.idmap or X-mount.owner hooks to clone filesystems with...

CVE-2026-76642: Detection of Error Condition Without Action

util-linux versions through 2.41.5 and 2.42.2 fail to check mount helper exit status before running post-mount hooks, allowing unprivileged users to execute privileged operations on pre-existing filesystems. Attackers can exploit X-mount.idmap or X-mount.owner hooks to clone filesystems with...

AZL-99390 CVE-2026-78410 affecting package util-linux for versions less than 2.40.2-6

A flaw was found in util-linux. Restricted bind mounts take the source path from fstab but do not pin that source before the privileged mount. A local unprivileged user who can replace the authorized source or a writable ancestor can redirect SUID mount8 to bind another host directory. If the fst...

CVE-2026-78410

A flaw was found in util-linux. Restricted bind mounts take the source path from fstab but do not pin that source before the privileged mount. A local unprivileged user who can replace the authorized source or a writable ancestor can redirect SUID mount8 to bind another host directory. If the fst...

ALPINE-CVE-2026-78410

A flaw was found in util-linux. Restricted bind mounts take the source path from fstab but do not pin that source before the privileged mount. A local unprivileged user who can replace the authorized source or a writable ancestor can redirect SUID mount8 to bind another host directory. If the fst...

ALPINE-CVE-2026-78409

The X-mount.subdir option uses a detached-tree fast path on Linux 6.15 and later and passes the configured subdirectory to opentree with ATSYMLINKNOFOLLOW. That flag does not stop intermediate symlink traversal or keep resolution inside the newly mounted filesystem. A local unprivileged user with...

DEBIAN-CVE-2026-78409

The X-mount.subdir option uses a detached-tree fast path on Linux 6.15 and later and passes the configured subdirectory to opentree with ATSYMLINKNOFOLLOW. That flag does not stop intermediate symlink traversal or keep resolution inside the newly mounted filesystem. A local unprivileged user with...

DEBIAN-CVE-2026-78410

A flaw was found in util-linux. Restricted bind mounts take the source path from fstab but do not pin that source before the privileged mount. A local unprivileged user who can replace the authorized source or a writable ancestor can redirect SUID mount8 to bind another host directory. If the fst...

CVE-2026-78410

A flaw was found in util-linux. Restricted bind mounts take the source path from fstab but do not pin that source before the privileged mount. A local unprivileged user who can replace the authorized source or a writable ancestor can redirect SUID mount8 to bind another host directory. If the fst...

UBUNTU-CVE-2026-78410

A flaw was found in util-linux. Restricted bind mounts take the source path from fstab but do not pin that source before the privileged mount. A local unprivileged user who can replace the authorized source or a writable ancestor can redirect SUID mount8 to bind another host directory. If the fst...

UBUNTU-CVE-2026-78409

The X-mount.subdir option uses a detached-tree fast path on Linux 6.15 and later and passes the configured subdirectory to opentree with ATSYMLINKNOFOLLOW. That flag does not stop intermediate symlink traversal or keep resolution inside the newly mounted filesystem. A local unprivileged user with...

CVE-2026-78409 Util-linux: util-linux: x-mount.subdir detached-tree resolution can escape via intermediate symlinks

The X-mount.subdir option uses a detached-tree fast path on Linux 6.15 and later and passes the configured subdirectory to opentree with ATSYMLINKNOFOLLOW. That flag does not stop intermediate symlink traversal or keep resolution inside the newly mounted filesystem. A local unprivileged user with...

EUVD-2026-70107

The X-mount.subdir option uses a detached-tree fast path on Linux 6.15 and later and passes the configured subdirectory to opentree with ATSYMLINKNOFOLLOW. That flag does not stop intermediate symlink traversal or keep resolution inside the newly mounted filesystem. A local unprivileged user with...

CVE-2026-78409

The X-mount.subdir option uses a detached-tree fast path on Linux 6.15 and later and passes the configured subdirectory to opentree with ATSYMLINKNOFOLLOW. That flag does not stop intermediate symlink traversal or keep resolution inside the newly mounted filesystem. A local unprivileged user with...

CVE-2026-78409

A flaw in util-linux 's X-mount.subdir mount option allows a local unprivileged user to escape the intended subdirectory and attach an arbitrary host path at the intended mountpoint. On Linux 6.15 and later , the option takes a detached-tree fast path that calls open_tree() with AT_SYMLINK_NOFOLL...

CVE-2026-78409

The X-mount.subdir option uses a detached-tree fast path on Linux 6.15 and later and passes the configured subdirectory to opentree with ATSYMLINKNOFOLLOW. That flag does not stop intermediate symlink traversal or keep resolution inside the newly mounted filesystem. A local unprivileged user with...

CVE-2026-78410

util-linux is affected by a flaw in how restricted bind mounts are handled. The source path taken from /etc/fstab is not pinned before the privileged mount(8) call, allowing a local unprivileged user who can replace the authorized source or a writable ancestor to redirect the SUID mount to bind a...