CVE-2026-64149

CVE CVE-2026-64149EUVD EUVD-2026-45834Published 2026-07-19T15:40:39.000Z

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: dma-mapping: move dma_map_resource() sanity check into debug code dma_map_resource() uses pfn_valid() to ensure the range is not RAM. However, pfn_valid() only checks for availability of the memory map for a PFN but it does not ensure that the PFN is actually backed by RAM. On ARM64 with SPARSEMEM (128MB section granularity), MMIO addresses that share a section with RAM will falsely trigger the WARN_ON_ONCE and cause dma_map_resource() to return DMA_MAPPING_ERROR. This causes a WARNING on Raspberry Pi 4 during spi_bcm2835 probe because the SPI FIFO register (0xfe204004) falls in the same sparsemem section as the end of RAM (0xf8000000-0xfbffffff), both in section 31 (0xf8000000-0xffffffff). Move the sanity check from dma_map_resource() into debug_dma_map_phys() and replace the unreliable pfn_valid() with pfn_valid() && !PageReserved(), which correctly identifies actual usable RAM without false positives for MMIO regions that happen to have struct pages. Since dma_map_resource() is dma_map_phys(DMA_ATTR_MMIO), the check applies equally to both APIs. Any non-reserved page represents kernel memory to a sufficient degree that using DMA_ATTR_MMIO on it is almost certainly wrong and risks breaking coherency on non-coherent platforms. ZONE_DEVICE pages used for PCI P2P DMA (MEMORY_DEVICE_PCI_P2PDMA) have PageReserved set, so they will not trigger a false positive. The check no longer blocks the mapping and uses err_printk() to integrate with dma-debug filtering.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux f7326196a781622b33bfbdabb00f5e72b5fb5679 <004a777879ff629f6e0ca3d09ad09fa3452bcc4d; patch: 0; f7326196a781622b33bfbdabb00f5e72b5fb5679 <181e67bc11c5ec5b87c6c512c2078752b23ca8d4; patch: 6.18.34; f7326196a781622b33bfbdabb00f5e72b5fb5679 <af0c3f05866237f7592219bfe05387bc3bfc99b5; 6.18; patch: 7.0.11; patch: 7.1

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

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