{"id":"CVE-2026-64323","summary":"udf: validate VAT header length against the VAT inode size","details":"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 checking it against the VAT inode\nsize:\n\n\tmap-\u003es_type_specific.s_virtual.s_start_offset =\n\t\tle16_to_cpu(vat20-\u003elengthHeader);\n\tmap-\u003es_type_specific.s_virtual.s_num_entries =\n\t\t(sbi-\u003es_vat_inode-\u003ei_size -\n\t\t\tmap-\u003es_type_specific.s_virtual.s_start_offset) \u003e\u003e 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 \u003e s_num_entries\" bound in\nudf_get_pblock_virt15(); and on the ICB-inline path that function reads\n\n\t((__le32 *)(iinfo-\u003ei_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.","modified":"2026-07-28T04:03:04.740652759Z","published":"2026-07-25T08:49:51.097Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64323.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0ad2d09a8d66fa8dc6f9b70d660b5fb4478ea934"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2900e02a0dd4fc30ac9840e7ce4ca0b041ab0d63"},{"type":"WEB","url":"https://git.kernel.org/stable/c/55287a3555ff0515b3aff181d2c08c0462a41709"},{"type":"WEB","url":"https://git.kernel.org/stable/c/74580fdf022909e184223cacc364feb826982d96"},{"type":"WEB","url":"https://git.kernel.org/stable/c/883962731420ec271ed8c1cd76524f4b17faa982"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d8202786b3d75125c84ebc4de6d946f92fde0ee8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e610fb113cdfa8bf4247c9bf4f2337b81ad4ddad"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64323.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64323"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"fa5e08156335d0687c85b4e724db9448fb166601"},{"fixed":"0ad2d09a8d66fa8dc6f9b70d660b5fb4478ea934"},{"fixed":"883962731420ec271ed8c1cd76524f4b17faa982"},{"fixed":"2900e02a0dd4fc30ac9840e7ce4ca0b041ab0d63"},{"fixed":"bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acb"},{"fixed":"55287a3555ff0515b3aff181d2c08c0462a41709"},{"fixed":"e610fb113cdfa8bf4247c9bf4f2337b81ad4ddad"},{"fixed":"74580fdf022909e184223cacc364feb826982d96"},{"fixed":"d8202786b3d75125c84ebc4de6d946f92fde0ee8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64323.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.26"},{"fixed":"5.10.261"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.212"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.178"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.145"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.96"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.39"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64323.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H"}]}