CVE-2026-98254

7.8 HIGH

Published 2026-10-06 · Updated 2026-10-07

AI risk analysis

Summary: The Linux kernel's SWIOTLB (Software I/O Translation Lookaside Buffer) has a bug where it incorrectly calculates memory addresses when handling highmem pages during DMA operations. This causes data to be written to the wrong memory page, potentially leading to data corruption or incorrect device behavior.
Exploitability: Exploitation is moderately difficult and requires specific conditions including DMA operations with highmem pages and non-zero tlb_offset values, typically triggered by partial DMA sync operations.
Blast radius: The impact affects systems using DMA operations with highmem memory regions, potentially causing data corruption in device communications and system instability, particularly in server or embedded environments with extensive DMA usage.
Detection: No reliable host or network indicator is derivable from the published description.
Prioritized remediation: Apply the kernel patch from the Linux kernel version 6.10-rc1 which fixes the SWIOTLB address calculation issue for highmem page lookups.

dmamemorykernel

Analysis generated locally by garnet-coder (no data left the box). AI-assisted — verify against primary sources before acting.

NVD 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 then hands a highmem address to phys_to_virt(). Take both from orig_addr once it is final and keep pfn in the branch that uses it. PhysHighMem() asks the question straight from the address, as dma-debug already does.

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

All references

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.

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