{"cve":"CVE-2024-35814","nvd":{"published":"2024-05-17T14:15:15.853","modified":"2026-08-04T11:17:55.957","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nswiotlb: Fix double-allocation of slots due to broken alignment handling\n\nCommit bbb73a103fbb (\"swiotlb: fix a braino in the alignment check fix\"),\nwhich was a fix for commit 0eee5ae10256 (\"swiotlb: fix slot alignment\nchecks\"), causes a functional regression with vsock in a virtual machine\nusing bouncing via a restricted DMA SWIOTLB pool.\n\nWhen virtio allocates the virtqueues for the vsock device using\ndma_alloc_coherent(), the SWIOTLB search can return page-unaligned\nallocations if 'area->index' was left unaligned by a previous allocation\nfrom the buffer:\n\n # Final address in brackets is the SWIOTLB address returned to the caller\n | virtio-pci 0000:00:07.0: orig_addr 0x0 alloc_size 0x2000, iotlb_align_mask 0x800 stride 0x2: got slot 1645-1649/7168 (0x98326800)\n | virtio-pci 0000:00:07.0: orig_addr 0x0 alloc_size 0x2000, iotlb_align_mask 0x800 stride 0x2: got slot 1649-1653/7168 (0x98328800)\n | virtio-pci 0000:00:07.0: orig_addr 0x0 alloc_size 0x2000, iotlb_align_mask 0x800 stride 0x2: got slot 1653-1657/7168 (0x9832a800)\n\nThis ends badly (typically buffer corruption and/or a hang) because\nswiotlb_alloc() is expecting a page-aligned allocation and so blindly\nreturns a pointer to the 'struct page' corresponding to the allocation,\ntherefore double-allocating the first half (2KiB slot) of the 4KiB page.\n\nFix the problem by treating the allocation alignment separately to any\nadditional alignment requirements from the device, using the maximum\nof the two as the stride to search the buffer slots and taking care\nto ensure a minimum of page-alignment for buffers larger than a page.\n\nThis also resolves swiotlb allocation failures occuring due to the\ninclusion of ~PAGE_MASK in 'iotlb_align_mask' for large allocations and\nresulting in alignment requirements exceeding swiotlb_max_mapping_size().","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","score":8.8},"cwes":["CWE-415","CWE-119","CWE-1055"],"references":["https://git.kernel.org/stable/c/04867a7a33324c9c562ee7949dbcaab7aaad1fb4","https://git.kernel.org/stable/c/3e7acd6e25ba77dde48c3b721c54c89cd6a10534","https://git.kernel.org/stable/c/777391743771040e12cc40d3d0d178f70c616491","https://git.kernel.org/stable/c/c88668aa6c1da240ea3eb4d128b7906e740d3cb8","https://git.kernel.org/stable/c/04867a7a33324c9c562ee7949dbcaab7aaad1fb4"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:50:30.954589733+00:00"},"epss":{"cve":"CVE-2024-35814","score":0.00236,"percentile":0.14644,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}