CVE-2026-53084
Received Received - Intake
BPF Task VMA Iterator Memory Access Vulnerability

Publication date: 2026-06-24

Last updated on: 2026-06-24

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: bpf: return VMA snapshot from task_vma iterator Holding the per-VMA lock across the BPF program body creates a lock ordering problem when helpers acquire locks that depend on mmap_lock: vm_lock -> i_rwsem -> mmap_lock -> vm_lock Snapshot the VMA under the per-VMA lock in _next() via memcpy(), then drop the lock before returning. The BPF program accesses only the snapshot. The verifier only trusts vm_mm and vm_file pointers (see BTF_TYPE_SAFE_TRUSTED_OR_NULL in verifier.c). vm_file is reference- counted with get_file() under the lock and released via fput() on the next iteration or in _destroy(). vm_mm is already correct because lock_vma_under_rcu() verifies vma->vm_mm == mm. All other pointers are left as-is by memcpy() since the verifier treats them as untrusted.
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Meta Information
Published
2026-06-24
Last Modified
2026-06-24
Generated
2026-06-25
AI Q&A
2026-06-24
EPSS Evaluated
N/A
NVD
CVE-2026-53084
EUVD
EUVD-2026-38952
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
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Exploitability
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's BPF (Berkeley Packet Filter) subsystem related to how Virtual Memory Areas (VMAs) are handled during iteration. Specifically, holding the per-VMA lock across the BPF program body causes a lock ordering problem involving multiple locks: vm_lock, i_rwsem, and mmap_lock. This can lead to potential deadlocks or inconsistent states.

The fix involves taking a snapshot of the VMA under the per-VMA lock using memcpy() in the _next() function, then releasing the lock before returning. The BPF program then accesses only this snapshot instead of the live VMA structure, preventing the lock ordering issue.

Additionally, the verifier trusts only certain pointers (vm_mm and vm_file) and manages their reference counts safely to avoid use-after-free or other memory issues.

Impact Analysis

This vulnerability can cause lock ordering problems in the Linux kernel, potentially leading to deadlocks or kernel instability when BPF programs interact with VMAs. Such issues can degrade system performance or cause crashes, impacting system reliability.

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