CVE-2026-49418
HighCVSS 8.8Exploitation Probability (EPSS)
Low risk21th percentile - higher than 21% of all known CVEs
Summary
Vulnerability in FreeBSD kernel when msync(MS_INVALIDATE) is called on a mapping of an unmanaged device object. Physical pages are marked invalid but remain in the pager's list, leading to a double free on object destruction.
Risk Assessment
An unprivileged local user with access to a memory-mapped I/O device can trigger a kernel use-after-free, potentially leading to privilege escalation.
Recommendation
Apply the FreeBSD patch. Restrict access to memory-mapped I/O devices for unprivileged users.
Original NVD description (English source)
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.