{"id":"CVE-2025-40044","title":"fs: udf: fix OOB read in lengthAllocDescs handling","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs: udf: fix OOB read in lengthAllocDescs handling\n\nWhen parsing Allocation Extent Descriptor, lengthAllocDescs comes from\non-disk data and must be validated against th…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 14496175b264d30c2045584ee31d062af2e3a660","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < d2ed9aa8ae50fb0d4ac5ab07e4c67ba7e9a24818","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1d1847812a1a5375c10a2a779338df643f79c047","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 918649364fbca7d5df72522ca795479edcd25f91","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < a70dcfa8d0a0cc530a6af59483dfca260b652c1b","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b57f2d7d3e6bb89ed82330c5fe106cdfa34d3e24","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 459404f858213967ccfff336c41747d8dd186d38","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3bd5e45c2ce30e239d596becd5db720f7eb83c99","Linux 2.6.12"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-15T21:56:23.726969Z"},"published":"2025-10-28","updated":"2026-10-15","sourceUpdated":"2026-10-15T22:02:36.730Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-40044","references":[{"url":"https://git.kernel.org/stable/c/14496175b264d30c2045584ee31d062af2e3a660"},{"url":"https://git.kernel.org/stable/c/d2ed9aa8ae50fb0d4ac5ab07e4c67ba7e9a24818"},{"url":"https://git.kernel.org/stable/c/1d1847812a1a5375c10a2a779338df643f79c047"},{"url":"https://git.kernel.org/stable/c/918649364fbca7d5df72522ca795479edcd25f91"},{"url":"https://git.kernel.org/stable/c/a70dcfa8d0a0cc530a6af59483dfca260b652c1b"},{"url":"https://git.kernel.org/stable/c/b57f2d7d3e6bb89ed82330c5fe106cdfa34d3e24"},{"url":"https://git.kernel.org/stable/c/459404f858213967ccfff336c41747d8dd186d38"},{"url":"https://git.kernel.org/stable/c/3bd5e45c2ce30e239d596becd5db720f7eb83c99"}],"tags":["cve.org"],"epss":0.00173,"epssPercentile":0.06658,"ingestedAt":"2026-10-15T22:48:25.538Z","slug":"CVE-2025-40044","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nfs: udf: fix OOB read in lengthAllocDescs handling\n\nWhen parsing Allocation Extent Descriptor, lengthAllocDescs comes from\non-disk data and must be validated against the block size. Crafted or\ncorrupted images may set lengthAllocDescs so that the total descriptor\nlength (sizeof(allocExtDesc) + lengthAllocDescs) exceeds the buffer,\nleading udf_update_tag() to call crc_itu_t() on out-of-bounds memory and\ntrigger a KASAN use-after-free read.\n\nBUG: KASAN: use-after-free in crc_itu_t+0x1d5/0x2b0 lib/crc-itu-t.c:60\nRead of size 1 at addr ffff888041e7d000 by task syz-executor317/5309\n\nCPU: 0 UID: 0 PID: 5309 Comm: syz-executor317 Not tainted 6.12.0-rc4-syzkaller-00261-g850925a8133c #0\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014\nCall Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:377 [inline]\n print_report+0x169/0x550 mm/kasan/report.c:488\n kasan_report+0x143/0x180 mm/kasan/report.c:601\n crc_itu_t+0x1d5/0x2b0 lib/crc-itu-t.c:60\n udf_update_tag+0x70/0x6a0 fs/udf/misc.c:261\n udf_write_aext+0x4d8/0x7b0 fs/udf/inode.c:2179\n extent_trunc+0x2f7/0x4a0 fs/udf/truncate.c:46\n udf_truncate_tail_extent+0x527/0x7e0 fs/udf/truncate.c:106\n udf_release_file+0xc1/0x120 fs/udf/file.c:185\n __fput+0x23f/0x880 fs/file_table.c:431\n task_work_run+0x24f/0x310 kernel/task_work.c:239\n exit_task_work include/linux/task_work.h:43 [inline]\n do_exit+0xa2f/0x28e0 kernel/exit.c:939\n do_group_exit+0x207/0x2c0 kernel/exit.c:1088\n __do_sys_exit_group kernel/exit.c:1099 [inline]\n __se_sys_exit_group kernel/exit.c:1097 [inline]\n __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1097\n x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n </TASK>\n\nValidate the computed total length against epos->bh->b_size.\n\nFound by Linux Verification Center (linuxtesting.org) with Syzkaller.\n\n## Affected\n\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 14496175b264d30c2045584ee31d062af2e3a660`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < d2ed9aa8ae50fb0d4ac5ab07e4c67ba7e9a24818`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1d1847812a1a5375c10a2a779338df643f79c047`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 918649364fbca7d5df72522ca795479edcd25f91`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < a70dcfa8d0a0cc530a6af59483dfca260b652c1b`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b57f2d7d3e6bb89ed82330c5fe106cdfa34d3e24`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 459404f858213967ccfff336c41747d8dd186d38`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3bd5e45c2ce30e239d596becd5db720f7eb83c99`\n- `Linux 2.6.12`\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":[]}