Kernel

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.Show less

util-linux is a random collection of Linux utilities. Prior to version 2.41.4, a TOCTOU (Time-of-Check-Time-of-Use) vulnerability has been identified in the SUID binary /usr/bin/mount from util-linux. The mount binary, when setting up loop devices, validates the source file path with user privileges via fork() + setuid() + realpath(), but subsequently re-canonicalizes and opens it with root privileges (euid=0) without verifying that the path has not been replaced between both operations. Neither O_NOFOLLOW, nor inode comparison, nor post-open fstat() are employed. This allows a local unprivileged user to replace the source file with a symlink pointing to any root-owned file or device during the race window, causing the SUID binary to open and mount it as root. Exploitation requires an /etc/fstab entry with user,loop options whose path points to a directory where the attacker has write permission, and that /usr/bin/mount has the SUID bit set (the default configuration on virtually all Linux distributions). The impact is unauthorized read access to root-protected files and block devices, including backup images, disk volumes, and any file containing a valid filesystem. This issue has been patched in version 2.41.4.Show less

A flaw was found in util-linux. Improper hostname canonicalization in the `login(1)` utility, when invoked with the `-h` option, can modify the supplied remote hostname before setting `PAM_RHOST`. A remote attacker could exploit this by providing a specially crafted hostname, potentially bypassing host-based Pluggable Authentication Modules (PAM) access control rules that rely on fully qualified domain names. This could lead to unauthorized access.Show less

wall in util-linux through 2.40, often installed with setgid tty permissions, allows escape sequences to be sent to other users' terminals through argv. (Specifically, escape sequences received from stdin are blocked, but escape sequences received from argv are not blocked.) There may be plausible scenarios where this leads to account takeover.Show less

A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows a local user on a vulnerable system to unmount other users' filesystems that are either world-writable themselves (like /tmp) or mounted in a world-writable directory. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.Show less

A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows an unprivileged local attacker to unmount FUSE filesystems that belong to certain other users who have a UID that is a prefix of the UID of the attacker in its string form. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.Show less

A flaw was found in the util-linux chfn and chsh utilities when compiled with Readline support. The Readline library uses an "INPUTRC" environment variable to get a path to the library config file. When the library cannot parse the specified file, it prints an error message containing data from the file. This flaw allows an unprivileged user to read root-owned files, potentially leading to privilege escalation. This flaw affects util-linux versions prior to 2.37.4.Show less

An integer overflow in util-linux through 2.37.1 can potentially cause a buffer overflow if an attacker were able to use system resources in a way that leads to a large number in the /proc/sysvipc/sem file. NOTE: this is unexploitable in GNU C Library environments, and possibly in all realistic environments.Show less

A flaw was found in the Linux kernels SELinux LSM hook implementation before version 5.7, where it incorrectly assumed that an skb would only contain a single netlink message. The hook would incorrectly only validate the first netlink message in the skb and allow or deny the rest of the messages within the skb with the granted permission without further processing.Show less

In util-linux before 2.32-rc1, bash-completion/umount allows local users to gain privileges by embedding shell commands in a mountpoint name, which is mishandled during a umount command (within Bash) by a different user, as demonstrated by logging in as root and entering umount followed by a tab character for autocompletion.Show less

The parse_dos_extended function in partitions/dos.c in the libblkid library in util-linux allows physically proximate attackers to cause a denial of service (memory consumption) via a crafted MSDOS partition table with an extended partition boot record at zero offset.Show less

(a) mount and (b) umount in util-linux 2.14.1, 2.17.2, and probably other versions allow local users to determine the existence of restricted directories by (1) using the --guess-fstype command-line option or (2) attempting to mount a non-existent device, which generates different error messages depending on whether the directory exists.Show less

The sg_build_indirect function in drivers/scsi/sg.c in Linux kernel 2.6.28-rc1 through 2.6.31-rc8 uses an incorrect variable when accessing an array, which allows local users to cause a denial of service (kernel OOPS and NULL pointer dereference), as demonstrated by using xcdroast to duplicate a CD. NOTE: this is only exploitable by users who can open the cdrom device.Show less

Integer overflow in the hrtimer_forward function (hrtimer.c) in Linux kernel 2.6.21-rc4, when running on 64-bit systems, allows local users to cause a denial of service (infinite loop) via a timer with a large expiry value, which causes the timer to always be expired.Show less