Bug 2492323 (CVE-2026-53084)

Summary: CVE-2026-53084 kernel: bpf: return VMA snapshot from task_vma iterator
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's Berkeley Packet Filter (BPF) subsystem. This vulnerability involves a lock ordering problem that occurs when BPF programs acquire certain locks that depend on the `mmap_lock`. This issue could potentially lead to system instability or unexpected behavior due to incorrect handling of virtual memory area (VMA) locks.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-06-24 18:05:43 UTC 
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.
Comment 1 Keith Grant 2026-06-26 18:04:27 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062407-CVE-2026-53084-15d3@gregkh/T