CVE-2026-80758: Linux 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.

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= bd54df5ea7cadac520e346d5f0fe5d58e635b6ba, < dba60d26e9dda3e157ad6b0934d4232f6c6904ee; >= bd54df5ea7cadac520e346d5f0fe5d58e635b6ba, < 12cd315a7b6a7d7db3f69d98bfe3909275e9451d; >= bd54df5ea7cadac520e346d5f0fe5d58e635b6ba, < 25408c62ed4ebcd491d0e9e4b4a5b512547512e4; >= bd54df5ea7cadac520e346d5f0fe5d58e635b6ba, < 1c7efabfbaf796f11000a46094a69955a01ec6cc
Linux	Linux	6.16

References

Timeline

Published: Sep 4, 2026
Last Modified: Sep 4, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-80758?

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.

How severe is CVE-2026-80758?

Severity scoring for CVE-2026-80758 is pending analysis.

How do I fix CVE-2026-80758?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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