{"id":"CVE-2026-98254","published":"2026-10-06T09:18:14.057","lastModified":"2026-10-07T07:17:06.683","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nswiotlb: use the adjusted address for the highmem page lookup\n\nswiotlb_bounce() reads the page frame number from the slot's recorded\norig_addr, then advances orig_addr by tlb_offset to reach the address\nthe caller asked about. The highmem branch mixes the two: the offset\nwithin the page comes from the adjusted address, the page from the value\nbefore it.\n\nOnce the adjustment crosses a page boundary the pair no longer describes\none location, and the whole copy lands one page below the intended one\nfor a positive tlb_offset, one above for a negative one. DMA_FROM_DEVICE\nwrites the device data over the wrong page and leaves the intended one\nstale, DMA_TO_DEVICE feeds the device from a page the mapping may not\ncover. Partial syncs through dma_sync_single_range_for_*() are what make\ntlb_offset non-zero.\n\nThe branch test is picked the same way, so a slot recorded in lowmem can\nbe adjusted into highmem and the lowmem path then hands a highmem\naddress to phys_to_virt().\n\nTake both from orig_addr once it is final and keep pfn in the branch\nthat uses it. PhysHighMem() asks the question straight from the address,\nas dma-debug already does.","cvssScore":7.8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/0219b72f5c209732b2f03a8cc0d7240b5e428a99","tags":[]},{"url":"https://git.kernel.org/stable/c/6e53b4d6afbde626255805d438cabb1cac482445","tags":[]},{"url":"https://git.kernel.org/stable/c/aa4709813b29db89f2307f968db5d24925dcdeb1","tags":[]},{"url":"https://git.kernel.org/stable/c/b7d7914a9ae3097e63d113007e4fb44d33d515b1","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":{"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.","remediation":"Apply the kernel patch from the Linux kernel version 6.10-rc1 which fixes the SWIOTLB address calculation issue for highmem page lookups.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["dma","memory","kernel"],"model":"garnet-coder","analyzedAt":"2026-10-14T09:04:44.168Z"}}