PT-2026-51867 · Linux · Linux

Published

2026-06-24

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Updated

2026-06-24

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CVE-2026-52973

None

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In the Linux kernel, the following vulnerability has been resolved:
futex: Drop CLONE THREAD requirement for private default hash alloc
Currently need futex hash allocate default() depends on strict pthread semantics, abusing CLONE THREAD. This breaks the non-concurrency assumptions when doing the mm->futex ref pcpu allocations, leading to bugs[0] when sharing the mm in other ways; ie:
BUG: KASAN: slab-use-after-free in futex hash put
... where the +1 bias can end up on a percpu counter that mm->futex ref no longer points at.
Loosen the check to cover any CLONE VM clone, except vfork(). Excluding vfork keeps the existing paths untouched (no overhead), and we can't race in the first place: either the parent is suspended and the child runs alone, or mm->futex ref is already allocated from an earlier CLONE VM.
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Related Identifiers

CVE-2026-52973

Affected Products

Linux