CVE-2026-98254

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

swiotlb: use the adjusted address for the highmem page lookup

swiotlb_bounce() reads the page frame number from the slot's recorded

orig_addr, then advances orig_addr by tlb_offset to reach the address

the caller asked about. The highmem branch mixes the two: the offset

within the page comes from the adjusted address, the page from the value

before it.

Once the adjustment crosses a page boundary the pair no longer describes

one location, and the whole copy lands one page below the intended one

for a positive tlb_offset, one above for a negative one. DMA_FROM_DEVICE

writes the device data over the wrong page and leaves the intended one

stale, DMA_TO_DEVICE feeds the device from a page the mapping may not

cover. Partial syncs through dma_sync_single_range_for_*() are what make

tlb_offset non-zero.

The branch test is picked the same way, so a slot recorded in lowmem can

be adjusted into highmem and the lowmem path the

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References