CVE-2026-93137

/// Technical description

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

bpf: Fix use-after-free on mm_struct in bpf_find_vma()

bpf_find_vma() reads task->mm and calls mmap_read_trylock(mm) without

holding a reference on the mm. On a foreign task, a concurrent exit_mm()

can free the mm_struct between the lockless read and the trylock,

resulting in a use-after-free. mm_struct is not SLAB_TYPESAFE_BY_RCU.

For the current task, task->mm is stable. For a foreign task, pin the mm

under task->alloc_lock and release it with mmput_async(), mirroring commit

d8e27d2d22b6 ("bpf: fix mm lifecycle in open-coded task_vma iterator").

Use spin_trylock() instead of get_task_mm() so BPF context does not block

on alloc_lock. Reject irqs-disabled contexts and !CONFIG_MMU on the

foreign-task path because dropping the mm reference is not safe there.

Race:

CPU0 (BPF program) CPU1 (exiting task)

============================ ==========================

bpf_find_vma(foreign_task):

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References