CVE-2026-52973 In the Linux kernel, the following vulnerability has been resolved: futex: Drop CLONE_THREAD requirement for private…
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.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux 7.1 | earliest → < 7.1 | 7.1 |
| Linux 7.0 | earliest → < 7.0.10 | 7.0.10 |
| Linux 6.18 | earliest → < 6.18.33 | 6.18.33 |
| Linux | 6.17 | No fix stated |
| Red Hat Enterprise Linux 10 | Versions not published | |
| Red Hat Enterprise Linux 9 | Versions not published | |
| Red Hat Enterprise Linux 7 | Versions not published | |
| Red Hat Enterprise Linux 8 | Versions not published | |
| Red Hat Enterprise Linux 6 | Versions not published |