{"id":"CVE-2026-64323","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nudf: validate VAT header length against the VAT inode size\n\nudf_load_vat() takes the virtual partition's start offset straight from\nthe on-disk VAT 2.0 header without c…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nudf: validate VAT header length against the VAT inode size\n\nudf_load_vat() takes the virtual partition's start offset straight from\nthe on-disk VAT 2.0 header without c…","severity":"high","cvss":7.1,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","published":"2026-07-25","updated":"2026-07-27","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-64323","references":[{"url":"https://git.kernel.org/stable/c/0ad2d09a8d66fa8dc6f9b70d660b5fb4478ea934","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2900e02a0dd4fc30ac9840e7ce4ca0b041ab0d63","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/55287a3555ff0515b3aff181d2c08c0462a41709","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/74580fdf022909e184223cacc364feb826982d96","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/883962731420ec271ed8c1cd76524f4b17faa982","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acb","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d8202786b3d75125c84ebc4de6d946f92fde0ee8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e610fb113cdfa8bf4247c9bf4f2337b81ad4ddad","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00164,"epssPercentile":0.06041,"ingestedAt":"2026-07-27T06:16:50.554Z","slug":"CVE-2026-64323","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nudf: validate VAT header length against the VAT inode size\n\nudf_load_vat() takes the virtual partition's start offset straight from\nthe on-disk VAT 2.0 header without checking it against the VAT inode\nsize:\n\n\tmap->s_type_specific.s_virtual.s_start_offset =\n\t\tle16_to_cpu(vat20->lengthHeader);\n\tmap->s_type_specific.s_virtual.s_num_entries =\n\t\t(sbi->s_vat_inode->i_size -\n\t\t\tmap->s_type_specific.s_virtual.s_start_offset) >> 2;\n\nlengthHeader is a fully attacker-controlled 16-bit value.  If it exceeds\nthe VAT inode size, the s_num_entries subtraction underflows to a huge\ncount, which defeats the \"block > s_num_entries\" bound in\nudf_get_pblock_virt15(); and on the ICB-inline path that function reads\n\n\t((__le32 *)(iinfo->i_data + s_start_offset))[block]\n\nso a large s_start_offset indexes past the inode's in-ICB data.  Mounting\na crafted UDF image with a virtual (VAT) partition then triggers an\nout-of-bounds read.\n\nReject a VAT whose header length does not leave room for at least one\nentry within the VAT inode.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}