CVE-2026-53085

Summary

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

bpf: fix mm lifecycle in open-coded task_vma iterator

The open-coded task_vma iterator reads task->mm locklessly and acquires mmap_read_trylock() but never calls mmget(). If the task exits concurrently, the mm_struct can be freed as it is not SLAB_TYPESAFE_BY_RCU, resulting in a use-after-free.

Safely read task->mm with a trylock on alloc_lock and acquire an mm reference. Drop the reference via bpf_iter_mmput_async() in _destroy() and error paths. bpf_iter_mmput_async() is a local wrapper around mmput_async() with a fallback to mmput() on !CONFIG_MMU.

Reject irqs-disabled contexts (including NMI) up front. Operations used by _next() and _destroy() (mmap_read_unlock, bpf_iter_mmput_async) take spinlocks with IRQs disabled (pool->lock, pi_lock). Running from NMI or from a tracepoint that fires with those locks held could deadlock.

A trylock on alloc_lock is used instead of the blocking task_lock() (get_task_mm) to avoid a deadlock when a softirq BPF program iterates a task that already holds its alloc_lock on the same CPU.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux4ac4546821584736798aaa9e97da9f6eaf689ea3 < 239cec25a22662dbd80f57d94b38178c8be95269affected
LinuxLinux4ac4546821584736798aaa9e97da9f6eaf689ea3 < d0862de7c866c5bd7c32531f66738c21197af888affected
LinuxLinux4ac4546821584736798aaa9e97da9f6eaf689ea3 < 43683bb280330f3d36f0f2a3932a4867b9603e9caffected
LinuxLinux4ac4546821584736798aaa9e97da9f6eaf689ea3 < d8e27d2d22b6e2df3a0125b8c08e9aace38c954caffected
LinuxLinux6.7affected
LinuxLinux0 < 6.7unaffected
LinuxLinux6.12.91 <= 6.12.*unaffected
LinuxLinux6.18.33 <= 6.18.*unaffected
LinuxLinux7.0.10 <= 7.0.*unaffected
LinuxLinux7.1 <= *unaffected

Weaknesses

ADP Enrichment

kernel: bpf: fix mm lifecycle in open-coded task_vma iterator

Additional References

References