Bug 2492323 (CVE-2026-53084) - CVE-2026-53084 kernel: bpf: return VMA snapshot from task_vma iterator
Summary: CVE-2026-53084 kernel: bpf: return VMA snapshot from task_vma iterator
Keywords:
Status: NEW
Alias: CVE-2026-53084
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-06-24 18:05 UTC by OSIDB Bzimport
Modified: 2026-06-26 18:06 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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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.


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