CVE-2026-98994 — statmount: read the parent of an unmounted mount under mount_lock

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

statmount: read the parent of an unmounted mount under mount_lock

statmount_mnt_basic() reads the ids of the parent through m->mnt_parent with namespace_sem held for reading. That's fine for a mount that is in a namespace. Everything above it is pinned by that namespace.

STATMOUNT_BY_FD also accepts a file descriptor on a mount that has been unmounted on purpose and that only the file descriptor keeps alive. If that mount stayed attached to its parent when it was unmounted the parent is unmounted as well and nothing pins it for the child.

The final mntput() unmounts the children under mount_lock alone and frees the parent afterwards. Concurrently, statmount_mnt_basic() reads m->mnt_parent twice while that can happen and can easily dereference a mount that's already gone.

Read the parent of an unmounted mount under mount_lock. The parent can't be put while it is held and both ids come from the same mount. A mounted mount's parent is pinned by the namespace and a mount can't leave its namespace while namespace_sem is held, so the common case takes no global lock.

USN-9018-1 — linux, linux-aws, linux-gcp, linux-ibm, linux-oem-7.0, linux-oracle vulnerabilities

Affected: Ubuntu:26.04:LTS: linux, Ubuntu:26.04:LTS: linux-aws, Ubuntu:26.04:LTS: linux-gcp, Ubuntu:26.04:LTS: linux-ibm, Ubuntu:26.04:LTS: linux-oem-7.0, Ubuntu:26.04:LTS: linux-oracle

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - Network file systems library; - Stream parser; - ARM64 architecture; - PowerPC architecture; - RISC-V architecture; - S390 architecture; - User-Mode Linux (UML); - x86 architecture; - Block layer subsystem; - Android drivers; - Bluetooth drivers; - TPM device driver; - DPLL subsystem; - EDAC drivers; - GPIO subsystem; - GPU drivers; - HID subsystem; - IIO subsystem; - IIO ADC drivers; - InfiniBand drivers; - Input Device (Miscellaneous) drivers; - Multiple devices driver; - MemoryStick subsystem; - MMC subsystem; - MTD block device drivers; - Network drivers; - Ethernet bonding driver; - Mellanox network drivers; - STMicroelectronics network drivers; - Ethernet team driver; - MediaTek network drivers; - NVME drivers; - Device tree and open firmware driver; - Power sequencing drivers; - Voltage and Current Regulator drivers; - Real Time Clock drivers; - SCSI subsystem; - Greybus lights staging drivers; - Trusted Execution Environment drivers; - Thunderbolt and USB4 drivers; - TTY drivers; - Cadence USB3 driver; - USB Device Class drivers; - USB core drivers; - DesignWare USB2 driver; - DesignWare USB3 driver; - USB Gadget drivers; - USB Serial drivers; - USB Mass Storage drivers; - USB Type-C suppor…

Most recent entries from all

CVE-2026-98994 — statmount: read the parent of an unmounted mount under mount_lock

USN-9018-1 — linux, linux-aws, linux-gcp, linux-ibm, linux-oem-7.0, linux-oracle vulnerabilities