{"id":"CVE-2026-68099","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: restore DACL size on check_add_overflow() to avoid malformed ACL\n\ncheck_add_overflow() unconditionally writes the truncated sum into *d\neven on overflow, per its…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: restore DACL size on check_add_overflow() to avoid malformed ACL\n\ncheck_add_overflow() unconditionally writes the truncated sum into *d\neven on overflow, per its…","severity":"none","published":"2026-08-10","updated":"2026-08-23","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-68099","references":[{"url":"https://git.kernel.org/stable/c/0bf38372821b1526f31538a7d9811844c55c7f38","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/847ecd4eb3c117c3d2f13f1e7ab506543aad8183","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8f3a7a499a7d9bb1c0f33fe78c4a4594d7e307f4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bbf0a8e931204ecdab494a88d43b0a24a04285c5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bc90144ce8bb7fcf05ad9417c7adb4e9509d9e13","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f4fcd0c1a243d449307b887fafee23921e9db5ab","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00173,"epssPercentile":0.0699,"ingestedAt":"2026-08-23T13:48:05.827Z","slug":"CVE-2026-68099","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: restore DACL size on check_add_overflow() to avoid malformed ACL\n\ncheck_add_overflow() unconditionally writes the truncated sum into *d\neven on overflow, per its contract in include/linux/overflow.h.\nThe four check_add_overflow() guards in set_posix_acl_entries_dacl()\nand set_ntacl_dacl() break out of the ACE-building loops on overflow,\nbut the truncated *size is then consumed downstream at the end of\nset_ntacl_dacl():\n\n    pndacl->size = cpu_to_le16(le16_to_cpu(pndacl->size) + size);\n\nThis produces an on-wire NT ACL whose pndacl->size under-reports the\nbytes actually written by the preceding fill_ace_for_sid()/memcpy()\ncalls, yielding a malformed ACL that can trigger out-of-bounds reads\nwhen re-parsed by clients or ksmbd itself.\n\nRestore *size to its pre-addition value on each overflow branch (via\n`*size -= ace_sz` / `size -= nt_ace_size`) so that after the break,\n*size once again holds the cumulative size of the successfully-written\nACEs. The committed ACL is then truncated-but-self-consistent rather\nthan malformed.\n\nThe ksmbd DACL builders are the only check_add_overflow() sites found\nwhere an overflow path breaks out of a loop and the destination value\nis consumed afterward. The other nearby break-style cases either\nreturn -EINVAL on overflow (transport_ipc.c) or break without\nconsuming the overflowed destination value afterward (buildid.c).\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}