{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98254", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.331Z", "datePublished": "2026-10-06T08:45:20.736Z", "dateUpdated": "2026-10-19T09:16:25.551Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:16:25.551Z" }, "descriptions": [ { "lang": "en", "value": "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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The defect is in swiotlb_bounce(), reached only via __swiotlb_sync_single_for_cpu/_for_device from a driver's dma_sync_single_range_for_*() on a bounced buffer. No protocol message carries malformed input, and a local user can only cause it by doing I/O on a highmem buffer through such a driver.\nAC:L - Not used; the AC line below is the real value.\nPR:L - The attacker needs an ordinary local account to issue I/O whose buffers (user or page-cache pages, which can be highmem) go through an affected device's streaming DMA mapping. No capability check on the swiotlb sync path stands in the way.\nUI:N - Once the attacker's own I/O drives the partial-sync pattern, no victim action is needed. The bounce runs inside the driver's sync call.\nS:U - The bad copy is done by the kernel's own swiotlb code into kernel-managed physical memory. No IOMMU, VM or other boundary is crossed beyond the kernel's own authority.\nC:H - On DMA_TO_DEVICE, memcpy_from_page() uses pfn_to_page(PFN_DOWN(old orig_addr)) and feeds the device a whole neighbouring physical page the mapping does not cover. This can expose unrelated kernel or user data to the device.\nI:H - On DMA_FROM_DEVICE, memcpy_to_page() writes device data over the page next to the intended one, corrupting arbitrary neighbouring memory. Separately, a lowmem slot shifted into highmem sends a highmem address to phys_to_virt() and memcpy() through a bogus pointer.\nA:H - Overwriting an unrelated physical page, or calling memcpy() on a bogus phys_to_virt() pointer for a highmem address, can corrupt kernel state or fault and oops the kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/dma/swiotlb.c" ], "versions": [ { "version": "5f89468e2f060031cd89fd4287298e0eaf246bf6", "lessThan": "6e53b4d6afbde626255805d438cabb1cac482445", "status": "affected", "versionType": "git" }, { "version": "5f89468e2f060031cd89fd4287298e0eaf246bf6", "lessThan": "aa4709813b29db89f2307f968db5d24925dcdeb1", "status": "affected", "versionType": "git" }, { "version": "5f89468e2f060031cd89fd4287298e0eaf246bf6", "lessThan": "0219b72f5c209732b2f03a8cc0d7240b5e428a99", "status": "affected", "versionType": "git" }, { "version": "5f89468e2f060031cd89fd4287298e0eaf246bf6", "lessThan": "b7d7914a9ae3097e63d113007e4fb44d33d515b1", "status": "affected", "versionType": "git" }, { "version": "e6108147dd91b94d1979b110f265710c254c99d5", "status": "affected", "versionType": "git" }, { "version": "e77b796eb9b7ca3c1c0d574d0c155f55b59ca8d5", "status": "affected", "versionType": "git" }, { "version": "5.10.47", "lessThan": "5.11", "status": "affected", "versionType": "semver" }, { "version": "5.12.14", "lessThan": "5.13", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/dma/swiotlb.c" ], "versions": [ { "version": "5.13", "status": "affected" }, { "version": "0", "lessThan": "5.13", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.54", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.8", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.12.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.18.54" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "7.2.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "7.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.47" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.12.14" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/6e53b4d6afbde626255805d438cabb1cac482445" }, { "url": "https://git.kernel.org/stable/c/aa4709813b29db89f2307f968db5d24925dcdeb1" }, { "url": "https://git.kernel.org/stable/c/0219b72f5c209732b2f03a8cc0d7240b5e428a99" }, { "url": "https://git.kernel.org/stable/c/b7d7914a9ae3097e63d113007e4fb44d33d515b1" } ], "title": "swiotlb: use the adjusted address for the highmem page lookup", "x_generator": { "engine": "bippy-1.2.0" } } } }