{"id":"CVE-2026-31704","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: use check_add_overflow() to prevent u16 DACL size overflow\n\nset_posix_acl_entries_dacl() and set_ntacl_dacl() accumulate ACE sizes\nin u16 variables","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: use check_add_overflow() to prevent u16 DACL size overflow\n\nset_posix_acl_entries_dacl() and set_ntacl_dacl() accumulate ACE sizes\nin u16 variables. When a file …","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.15, < 6.6.136","linux_kernel >= 6.7, < 6.12.84","linux_kernel >= 6.13, < 6.18.25","linux_kernel >= 6.19, < 7.0.2"],"patched":["linux_kernel 7.0.2"],"published":"2026-05-01","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:19:18.803","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-31704","references":[{"url":"https://git.kernel.org/stable/c/299f962c0b02d048fb45d248b4da493d03f3175d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/41e53a773db6342ac9a689ee5ba635c31744c9f0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8d5729350b236896f51379588d9a690b7fafb8db","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e1955a94b6f17f4b058afa955a6f187eb3ed7615","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00162,"epssPercentile":0.05036,"ingestedAt":"2026-10-15T03:30:12.867Z","slug":"CVE-2026-31704","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: use check_add_overflow() to prevent u16 DACL size overflow\n\nset_posix_acl_entries_dacl() and set_ntacl_dacl() accumulate ACE sizes\nin u16 variables. When a file has many POSIX ACL entries, the\naccumulated size can wrap past 65535, causing the pointer arithmetic\n(char *)pndace + *size to land within already-written ACEs. Subsequent\nwrites then overwrite earlier entries, and pndacl->size gets a\ntruncated value.\n\nUse check_add_overflow() at each accumulation point to detect the\nwrap before it corrupts the buffer, consistent with existing\ncheck_mul_overflow() usage elsewhere in smbacl.c.\n\n## Affected\n\n- `linux_kernel >= 5.15, < 6.6.136`\n- `linux_kernel >= 6.7, < 6.12.84`\n- `linux_kernel >= 6.13, < 6.18.25`\n- `linux_kernel >= 6.19, < 7.0.2`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 7.0.2`","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}