Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: futex: Avoid private hash use-after-free on final put futex_private_hash_put() drops the reference to fph before evaluating fph->mm for wake_up_var(). futex_ref_put() enables preemption again before returning. If that put drops the final reference and the task is preempted, another task can pivot to the replacement hash and free the old hash after an RCU grace period. The first task then reads fph->mm from the freed allocation when it resumes. KASAN reports a slab-use-after-free in futex_private_hash_put(), with the read at offset 24 in a freed kmalloc-512 allocation. The allocation and free stacks point to futex_hash_allocate() and the RCU free path, respectively. Load the mm pointer while the fph reference is still held and pass the saved value to wake_up_var(). wake_up_var() uses the pointer as a waitqueue key and does not dereference the mm through it.
References
- https://git.kernel.org/stable/c/12cd315a7b6a7d7db3f69d98bfe3909275e9451d
- https://git.kernel.org/stable/c/1c7efabfbaf796f11000a46094a69955a01ec6cc
- https://git.kernel.org/stable/c/25408c62ed4ebcd491d0e9e4b4a5b512547512e4
- https://git.kernel.org/stable/c/dba60d26e9dda3e157ad6b0934d4232f6c6904ee
FAQ
What is CVE-2026-80758?
CVE-2026-80758 is a documented vulnerability. In the Linux kernel, the following vulnerability has been resolved: futex: Avoid private hash use-after-free on final put futex_private_hash_put() drops the reference to fph before evaluating fph->m...
How severe is CVE-2026-80758?
CVSS scoring is not yet available for CVE-2026-80758. Check NVD for updates.
Is there a patch for CVE-2026-80758?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.