Executive brief
A vulnerability was identified in the Linux kernel's process information system (procfs). This component is responsible for providing information about running programs to the operating system and users. An error in how the kernel tracks parent-child relationships between programs could lead to a system crash or unpredictable behavior when a user or application attempts to read process statistics.
Technical details
A use-after-free (UAF) vulnerability exists in the Linux kernel's procfs subsystem within 'fs/proc/array.c'. The function 'do_task_stat()', which handles reads of '/proc/[pid]/stat', accesses 'task->real_parent' without proper Read-Copy-Update (RCU) protection. This creates a race condition where 'release_task' can be called on another CPU, leading to the deallocation of the parent task structure before 'do_task_stat' finishes its access. An attacker with local access could potentially exploit this race to cause a kernel oops or system instability. The fix replaces the direct access with 'task_ppid_nr_ns()', which implements the necessary RCU locking.
Affected products
- Linux Linux Kernel All versions prior to the fix in 2026
Timeline
- 2026-01-28: other: Patch submitted by Jinliang Zheng
- 2026-06-03: advisory: CVE-2026-46259 published by NVD
References
- https://git.kernel.org/stable/c/0e64bd46a04a4fd61279aca9f53a664e9e5f7e7e
- https://git.kernel.org/stable/c/1c8dc5b5517546c68ffae40b948336122bb61306
- https://git.kernel.org/stable/c/4f9ae386861e280b7631ca252f798d25575627ee
- https://git.kernel.org/stable/c/73ec7c96601d61d52310c659145bb06d933a0fa6
- https://git.kernel.org/stable/c/76149d53502cf17ef3ae454ff384551236fba867
- https://git.kernel.org/stable/c/c93a33f28f915d446eea6fb3f0e1def0b3af1982
- https://git.kernel.org/stable/c/dd8b13cb4ff1a4545a214ed897fdf2bc341155b6