{"id":"CVE-2026-97991","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nvdpa_sim_blk: reject out-of-range sector starts\n\nvdpasim_blk_check_range() logs an invalid start sector but continues\nvalidating the request","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nvdpa_sim_blk: reject out-of-range sector starts\n\nvdpasim_blk_check_range() logs an invalid start sector but continues\nvalidating the request.  The subsequent unsigned c…","severity":"high","vendor":"Linux","product":"Linux","affected":["Linux >= 7d189f617f83f780915b737896a696ff605bd19f < 14acb0d44b7d90a077beb7b92b444b90bafda9d9","Linux >= 7d189f617f83f780915b737896a696ff605bd19f < a8a1413a2cfdbedc896249f461d6d92efbbfe21f","Linux >= 7d189f617f83f780915b737896a696ff605bd19f < d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf","Linux >= 7d189f617f83f780915b737896a696ff605bd19f < 0a8693f00c408d85f086ad85d29e7030bf1e2055","Linux 5.13"],"published":"2026-09-25","updated":"2026-09-25","sourceUpdated":"2026-09-25T11:17:27.220","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-97991","references":[{"url":"https://git.kernel.org/stable/c/0a8693f00c408d85f086ad85d29e7030bf1e2055","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/14acb0d44b7d90a077beb7b92b444b90bafda9d9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a8a1413a2cfdbedc896249f461d6d92efbbfe21f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-25T11:06:38.864Z","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H","cvssSource":"cna","slug":"CVE-2026-97991","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nvdpa_sim_blk: reject out-of-range sector starts\n\nvdpasim_blk_check_range() logs an invalid start sector but continues\nvalidating the request.  The subsequent unsigned capacity subtraction can\nunderflow and let an out-of-range buffer offset reach the data path.\n\nThe invalid offset is used by three request paths.  VIRTIO_BLK_T_OUT\ncopies guest data to blk->buffer + offset through\nvringh_iov_pull_iotlb(), causing an out-of-bounds write in\n_copy_from_iter() or memcpy().  VIRTIO_BLK_T_IN copies from\nblk->buffer + offset to the guest through vringh_iov_push_iotlb(),\ncausing an out-of-bounds read in _copy_to_iter().\nVIRTIO_BLK_T_WRITE_ZEROES passes blk->buffer + offset to memset(),\ncausing an out-of-bounds write.\n\nReject starts at or beyond the capacity before the subtraction.  Treat the\ncapacity boundary as invalid because the IN and OUT paths round byte counts\ndown to sectors for validation but later copy the original byte counts.  A\nsub-sector request at the capacity boundary would otherwise still access\npast the end of the buffer.\n\nI found this bug myself, though the patch was written with AI assistance.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":210938,"id":"CVE-2026-97991","ts":1790349117271,"field":"cvss","old":null,"new":"7.8"},{"seq":210937,"id":"CVE-2026-97991","ts":1790349117271,"field":"severity","old":"none","new":"high"}]}