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CVE-2026-80778

Unknown

Last modified

CVE-2026-80778 is a vulnerability of currently unknown severity. In the Linux kernel, the following vulnerability has been resolved: futex/pi: Reject cross-mm private futex owners A private futex key borrows the waiter's mm without taking an mm_users reference. Nevertheless, attach_to_pi_owner() currently accepts an owner from a different address space and copies the private key into the owner's PI state. When that owner exits, exit_pi_state_list() uses the saved key to find the hash bucket and acquires a reference to the waiter's private hash.

Description

In the Linux kernel, the following vulnerability has been resolved: futex/pi: Reject cross-mm private futex owners A private futex key borrows the waiter's mm without taking an mm_users reference. Nevertheless, attach_to_pi_owner() currently accepts an owner from a different address space and copies the private key into the owner's PI state. When that owner exits, exit_pi_state_list() uses the saved key to find the hash bucket and acquires a reference to the waiter's private hash. If the last user of the waiter's mm exits concurrently, futex_hash_free() frees the hash while the owner still uses its bucket and reference. Prevent this by validating in attach_to_pi_owner() that, for private futexes, the owner mm and waiter mm are the same. Perform the check with the owner's pi_lock held and after validating owner::futex::state to serialize against a concurrent PI-state exit cleanup. [ tglx: Amended comment ]

Affected Software

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

VendorProductVersions
LinuxLinux>= 80367ad01d93ac781b0e1df246edaf006928002f, < 2b92e5562653b5293529f63b0300837d9dcedbd7; >= 80367ad01d93ac781b0e1df246edaf006928002f, < f7fb3e07752688842cbe0b85cf0d98c2fbf76b68; >= 80367ad01d93ac781b0e1df246edaf006928002f, < 43b148d796aa338858792d0167cebdc12b8cb4b9; >= 80367ad01d93ac781b0e1df246edaf006928002f, < 59b3732f95dda1fbd2234514d35f4fb6b5bb6d85
LinuxLinux6.16

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-80778?
In the Linux kernel, the following vulnerability has been resolved: futex/pi: Reject cross-mm private futex owners A private futex key borrows the waiter's mm without taking an mm_users reference. Nevertheless, attach_to_pi_owner() currently accepts an owner from a different address space and copies the private key into the owner's PI state. When that owner exits, exit_pi_state_list() uses the saved key to find the hash bucket and acquires a reference to the waiter's private hash. If the last user of the waiter's mm exits concurrently, futex_hash_free() frees the hash while the owner still uses its bucket and reference. Prevent this by validating in attach_to_pi_owner() that, for private futexes, the owner mm and waiter mm are the same. Perform the check with the owner's pi_lock held and after validating owner::futex::state to serialize against a concurrent PI-state exit cleanup. [ tglx: Amended comment ]
How severe is CVE-2026-80778?
Severity scoring for CVE-2026-80778 is pending analysis.
How do I fix CVE-2026-80778?
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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Source: NVD / NIST