CVE-2026-64149: In the Linux kernel, the following vulnerability has been resolved: dma-mapping: move dma_map_resource() sanity check i
Summary
A bug in the Linux kernel's dma_map_resource() function (which maps memory regions for direct memory access operations) was incorrectly blocking legitimate MMIO (memory-mapped input/output, hardware registers accessed like memory) mappings on ARM64 systems with SPARSEMEM (a memory management feature that divides physical memory into sections). The function used an unreliable check that falsely flagged MMIO addresses as RAM when they shared the same memory section, causing failures on devices like Raspberry Pi 4.
Solution / Mitigation
The fix moves the sanity check from dma_map_resource() into debug_dma_map_phys() and replaces the unreliable pfn_valid() check with a more accurate one: 'pfn_valid() && !PageReserved()' which correctly identifies actual usable RAM without false positives for MMIO regions. The check no longer blocks the mapping and uses err_printk() to integrate with dma-debug filtering.
Vulnerability Details
EPSS: 0.0%
July 19, 2026
Classification
Original source: https://nvd.nist.gov/vuln/detail/CVE-2026-64149
First tracked: July 19, 2026 at 02:09 PM
Classified by LLM (prompt v3) · confidence: 95%