CVE-2026-49418

Summary

When msync(MS_INVALIDATE) is called on a mapping of an unmanaged device object, the physical pages in the mapping range are marked invalid but remain in the pager's page list. A subsequent page fault will cause the fault handler to re-insert the page into the object's list. This corrupts the list, and on object destruction the page is freed twice.

An unprivileged local user with access to a device that provides memory-mapped I/O can trigger a use-after-free in the kernel, though this is limited to a pool of objects ("fictitious pages") that are never recycled for a different purpose. It may be possible to exploit this to escalate privileges.

Affected Software

Weaknesses

• CWE-416: CWE-416: Use After Free

References

• https://security.freebsd.org/advisories/FreeBSD-SA-26:37.vm.asc

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