{"id":"CVE-2026-53392","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4/flexfiles: reject zero filehandle version count\n\nff_layout_alloc_lseg() decodes the filehandle-version array count\nfrom the flexfiles layout body","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4/flexfiles: reject zero filehandle version count\n\nff_layout_alloc_lseg() decodes the filehandle-version array count\nfrom the flexfiles layout body. The value is us…","severity":"none","published":"2026-07-19","updated":"2026-07-19","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-53392","references":[{"url":"https://git.kernel.org/stable/c/2131ed64b767ffa8bcdb3677d90f3964e39aabc8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2c6bb3c40bc24f6aa8dfbe6fe98c3ad6389203f2","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7779c85028a0676fb190cde4f0c540f4f8e97761","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d8c90c7cc061265d5f2813a1f5c82ef2f4707e67","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"ingestedAt":"2026-07-19T21:33:34.561Z","epss":0.00529,"epssPercentile":0.4352,"slug":"CVE-2026-53392","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4/flexfiles: reject zero filehandle version count\n\nff_layout_alloc_lseg() decodes the filehandle-version array count\nfrom the flexfiles layout body. The value is used as the count for\nkzalloc_objs(), and the current code only rejects NULL.\n\nA zero count yields ZERO_SIZE_PTR, which can be stored in\ndss_info->fh_versions even though later flexfiles paths assume that at\nleast one filehandle version exists.\n\nReject fh_count == 0 before the allocation, matching the existing zero\nversion_count validation in the flexfiles GETDEVICEINFO parser.\n\nA QEMU/KASAN run with a malformed flexfiles layout hit:\n\n  KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]\n  RIP: 0010:ff_layout_encode_ff_layoutupdate.isra.0+0x15f/0x750\n  ff_layout_encode_layoutreturn+0x683/0x970\n  nfs4_xdr_enc_layoutreturn+0x278/0x3a0\n  Kernel panic - not syncing: Fatal exception\n\nThe patched kernel rejects the malformed layout without KASAN/oops/panic,\nand a valid fh_count=1 regression still opens, reads, and unmounts cleanly.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}