CVE-2026-64289

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> iommufd: Set upper bounds on cache invalidation entry_num and entry_len<br /> <br /> iommufd_hwpt_invalidate() takes a user-controlled entry_num and entry_len,<br /> each bounded only by U32_MAX. An entry_len beyond the kernel&amp;#39;s struct size<br /> makes the copy helper verify the extra bytes are zero, scanning that excess<br /> in one uninterruptible pass; a multi-gigabyte value over zeroed user memory<br /> trips the soft-lockup watchdog.<br /> <br /> A large entry_num is the other half, driving the backend invalidation loop<br /> with no reschedule. The VT-d nested handler, for one, copies each entry and<br /> flushes caches per iteration, pinning the CPU on a non-preemptible kernel.<br /> <br /> Cap both in the ioctl. entry_len is held under PAGE_SIZE, above any request<br /> struct, and entry_num under 1