{"id":"CVE-2026-64324","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nudf: validate free block extents against the partition length\n\nudf_free_blocks() checks the logical block number and count against the\npartition length, but drops the e…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nudf: validate free block extents against the partition length\n\nudf_free_blocks() checks the logical block number and count against the\npartition length, but drops the e…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","published":"2026-07-25","updated":"2026-07-27","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-64324","references":[{"url":"https://git.kernel.org/stable/c/12af328d2ee8d68e81ba612246d0b54b22d23e1f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/335202ab25b01fdd45889ff25eab70864686dea3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5f0419457f89dce1a3f1c8e62a3adf2f39ab8168","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9442d75429b0c556292a7454fe888d54259f5240","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b54aee5652fcd7c23a0904a4623ec462c3edc70c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/be87de7789a82a030a4896bc7683415ec9fa6f2b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/fb49099206c5c57af28a157249fa7bcb5518f99e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/fdd6229d2ae9914c1f25d1041db0f4f312a4fa76","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"epss":0.00161,"epssPercentile":0.05219,"ingestedAt":"2026-07-27T06:16:50.580Z","vendor":"Linux","product":"Linux","affected":["Linux >= 934f815345c09c290a9b9a9cfdddc203ec2117e8 < fdd6229d2ae9914c1f25d1041db0f4f312a4fa76","Linux >= 22cc7323f090646c8cfb5939e6f15bdc2ed3fd27 < b54aee5652fcd7c23a0904a4623ec462c3edc70c","Linux >= 7c4fa9ebfce69619d132fe703dc2e2cf62a13723 < 12af328d2ee8d68e81ba612246d0b54b22d23e1f","Linux >= 5cc9745e2ea11aef7d5c9a42bc36f6cd3e1b4cc3 < fb49099206c5c57af28a157249fa7bcb5518f99e","Linux >= 56e69e59751d20993f243fb7dd6991c4e522424c < 9442d75429b0c556292a7454fe888d54259f5240","Linux >= 56e69e59751d20993f243fb7dd6991c4e522424c < 335202ab25b01fdd45889ff25eab70864686dea3","Linux >= 56e69e59751d20993f243fb7dd6991c4e522424c < be87de7789a82a030a4896bc7683415ec9fa6f2b","Linux >= 56e69e59751d20993f243fb7dd6991c4e522424c < 5f0419457f89dce1a3f1c8e62a3adf2f39ab8168","Linux 097420e48e30f51e8f4f650b5c946f5af63ec1a3","Linux 5def895b42ef16a2da6402818cba8d7ec8ede1ef","Linux 05fb2bf477d3fe5421bd4cb699574737f52bd88b","Linux >= 5.10.224 < 5.10.261","Linux >= 5.15.165 < 5.15.212","Linux >= 6.1.105 < 6.1.178","Linux >= 6.6.46 < 6.6.145","Linux >= 4.19.320 < 4.20","Linux >= 5.4.282 < 5.5","Linux >= 6.10.5 < 6.11","Linux 6.11"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:39:12.321827Z"},"slug":"CVE-2026-64324","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nudf: validate free block extents against the partition length\n\nudf_free_blocks() checks the logical block number and count against the\npartition length, but drops the extent offset from that final bound.  A\ncrafted extent can pass the guard while logicalBlockNum + offset + count\npoints past the partition, which later indexes past the space bitmap\narray.\n\nA single ftruncate(2) on a file backed by such an extent reliably\npanics the kernel.  This is a local availability issue.  On desktop\nsystems where UDisks/polkit allows the active user to mount removable\nUDF media without CAP_SYS_ADMIN, an unprivileged local user can supply\nthe crafted filesystem and trigger the panic by truncating a writable\nfile on it.  Systems that require root or CAP_SYS_ADMIN to mount the\nimage have a higher prerequisite.\n\nNo confidentiality or integrity impact is claimed: the reproduced\nprimitive is an out-of-bounds read of a bitmap pointer slot followed by\na kernel panic.\n\nUse the already computed logicalBlockNum + offset + count value for the\npartition length check.  Also make load_block_bitmap() reject an\nout-of-range block group before indexing s_block_bitmap[], so corrupted\ncallers cannot walk past the flexible array.\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":[]}