{"id":"CVE-2026-74544","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_u32: validate offshift to prevent shift-out-of-bounds\n\nu32_change() copies the user-provided tc_u32_sel.offshift (unsigned char,\n0-255) into the kernel k…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_u32: validate offshift to prevent shift-out-of-bounds\n\nu32_change() copies the user-provided tc_u32_sel.offshift (unsigned char,\n0-255) into the kernel k…","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","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9990cac513e8b191de2ee589051ea7ebf3cee940","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 313cb9ffc4101a885d791facf4b5ea3d5e06144d","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < aef96eead2860cbfa371e4471d4f04412213b958","Linux 2.6.12"],"published":"2026-08-15","updated":"2026-10-15","sourceUpdated":"2026-10-15T11:17:47.287","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74544","references":[{"url":"https://git.kernel.org/stable/c/313cb9ffc4101a885d791facf4b5ea3d5e06144d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9990cac513e8b191de2ee589051ea7ebf3cee940","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/aef96eead2860cbfa371e4471d4f04412213b958","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"epss":0.00165,"epssPercentile":0.05338,"ingestedAt":"2026-10-15T11:00:41.671Z","slug":"CVE-2026-74544","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_u32: validate offshift to prevent shift-out-of-bounds\n\nu32_change() copies the user-provided tc_u32_sel.offshift (unsigned char,\n0-255) into the kernel knode object without bounds validation. When a\npacket later hits u32_classify() with TC_U32_VAROFFSET set, it evaluates\n`ntohs(offmask & *data) >> offshift` where the left operand is a 16-bit\nvalue promoted to a 32-bit int. Any offshift >= 32 is undefined behavior\nper C11 6.5.7p3, triggerable by an unprivileged user via user/network\nnamespaces.\n\nUBSAN: shift-out-of-bounds in net/sched/cls_u32.c:236:43\nshift exponent 32 is too large for 32-bit type int\n\nFix this by rejecting offshift >= 16 during filter creation in\nu32_change().\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":[]}