CVE-2026-52973
Full vulnerability record from the local CVENow database.
Description
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.
Severity
HIGH
CVSS score
7.8
(v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-06-24 17:17:07.840000
Last modified
2026-10-19 20:18:51.903000
View original CVE JSON
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Drop CLONE_THREAD requirement for private default hash alloc\n\nCurrently need_futex_hash_allocate_default() depends on strict pthread\nsemantics, abusing CLONE_THREAD. This breaks the non-concurrency\nassumptions when doing the mm->futex_ref pcpu allocations, leading to\nbugs[0] when sharing the mm in other ways; ie:\n\n BUG: KASAN: slab-use-after-free in futex_hash_put\n\n... where the +1 bias can end up on a percpu counter that mm->futex_ref\nno longer points at.\n\nLoosen the check to cover any CLONE_VM clone, except vfork(). Excluding\nvfork keeps the existing paths untouched (no overhead), and we can't\nrace in the first place: either the parent is suspended and the child\nruns alone, or mm->futex_ref is already allocated from an earlier\nCLONE_VM."
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