{"id":"CVE-2026-31704","summary":"ksmbd: use check_add_overflow() to prevent u16 DACL size overflow","details":"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 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-\u003esize 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.","modified":"2026-06-18T03:55:46.328503302Z","published":"2026-05-01T13:56:03.243Z","related":["CGA-rw65-cv7j-7vgm","openSUSE-SU-2026:10793-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31704.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/299f962c0b02d048fb45d248b4da493d03f3175d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/41e53a773db6342ac9a689ee5ba635c31744c9f0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8d5729350b236896f51379588d9a690b7fafb8db"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e1955a94b6f17f4b058afa955a6f187eb3ed7615"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31704.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31704"},{"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":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9"},{"fixed":"41e53a773db6342ac9a689ee5ba635c31744c9f0"},{"fixed":"8d5729350b236896f51379588d9a690b7fafb8db"},{"fixed":"e1955a94b6f17f4b058afa955a6f187eb3ed7615"},{"fixed":"5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43"},{"fixed":"ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7"},{"fixed":"299f962c0b02d048fb45d248b4da493d03f3175d"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-31704.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.15.0"},{"fixed":"6.1.175"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.136"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.84"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.25"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.2"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-31704.json"}}],"schema_version":"1.7.5"}