{"id":"CVE-2026-68099","state":"PUBLISHED","title":"ksmbd: restore DACL size on check_add_overflow() to avoid malformed ACL","description":"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 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).","publishedAt":"2026-08-10T11:58:13.940Z","updatedAt":"2026-08-23T12:45:49.075Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"41e53a773db6342ac9a689ee5ba635c31744c9f0","status":"affected","lessThan":"8f3a7a499a7d9bb1c0f33fe78c4a4594d7e307f4","versionType":"git"},{"version":"8d5729350b236896f51379588d9a690b7fafb8db","status":"affected","lessThan":"f4fcd0c1a243d449307b887fafee23921e9db5ab","versionType":"git"},{"version":"e1955a94b6f17f4b058afa955a6f187eb3ed7615","status":"affected","lessThan":"0bf38372821b1526f31538a7d9811844c55c7f38","versionType":"git"},{"version":"5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43","status":"affected","lessThan":"847ecd4eb3c117c3d2f13f1e7ab506543aad8183","versionType":"git"},{"version":"299f962c0b02d048fb45d248b4da493d03f3175d","status":"affected","lessThan":"bc90144ce8bb7fcf05ad9417c7adb4e9509d9e13","versionType":"git"},{"version":"299f962c0b02d048fb45d248b4da493d03f3175d","status":"affected","lessThan":"bbf0a8e931204ecdab494a88d43b0a24a04285c5","versionType":"git"},{"version":"ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7","status":"affected","versionType":"git"},{"version":"6.1.175","status":"affected","lessThan":"6.1.184","versionType":"semver"},{"version":"6.6.136","status":"affected","lessThan":"6.6.148","versionType":"semver"},{"version":"6.12.84","status":"affected","lessThan":"6.12.101","versionType":"semver"},{"version":"6.18.25","status":"affected","lessThan":"6.18.42","versionType":"semver"},{"version":"7.0.2","status":"affected","lessThan":"7.1","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smbacl.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"6.1.184","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smbacl.c"]}],"references":["https://git.kernel.org/stable/c/8f3a7a499a7d9bb1c0f33fe78c4a4594d7e307f4","https://git.kernel.org/stable/c/f4fcd0c1a243d449307b887fafee23921e9db5ab","https://git.kernel.org/stable/c/0bf38372821b1526f31538a7d9811844c55c7f38","https://git.kernel.org/stable/c/847ecd4eb3c117c3d2f13f1e7ab506543aad8183","https://git.kernel.org/stable/c/bc90144ce8bb7fcf05ad9417c7adb4e9509d9e13","https://git.kernel.org/stable/c/bbf0a8e931204ecdab494a88d43b0a24a04285c5"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/68xxx/CVE-2026-68099.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-68099","state":"PUBLISHED","datePublished":"2026-08-10T11:58:13.940Z","dateUpdated":"2026-08-23T12:45:49.075Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-30T09:28:09.368Z"},"containers":{"cna":{"title":"ksmbd: restore DACL size on check_add_overflow() to avoid malformed ACL","descriptions":[{"lang":"en","value":"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 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)."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"41e53a773db6342ac9a689ee5ba635c31744c9f0","status":"affected","lessThan":"8f3a7a499a7d9bb1c0f33fe78c4a4594d7e307f4","versionType":"git"},{"version":"8d5729350b236896f51379588d9a690b7fafb8db","status":"affected","lessThan":"f4fcd0c1a243d449307b887fafee23921e9db5ab","versionType":"git"},{"version":"e1955a94b6f17f4b058afa955a6f187eb3ed7615","status":"affected","lessThan":"0bf38372821b1526f31538a7d9811844c55c7f38","versionType":"git"},{"version":"5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43","status":"affected","lessThan":"847ecd4eb3c117c3d2f13f1e7ab506543aad8183","versionType":"git"},{"version":"299f962c0b02d048fb45d248b4da493d03f3175d","status":"affected","lessThan":"bc90144ce8bb7fcf05ad9417c7adb4e9509d9e13","versionType":"git"},{"version":"299f962c0b02d048fb45d248b4da493d03f3175d","status":"affected","lessThan":"bbf0a8e931204ecdab494a88d43b0a24a04285c5","versionType":"git"},{"version":"ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7","status":"affected","versionType":"git"},{"version":"6.1.175","status":"affected","lessThan":"6.1.184","versionType":"semver"},{"version":"6.6.136","status":"affected","lessThan":"6.6.148","versionType":"semver"},{"version":"6.12.84","status":"affected","lessThan":"6.12.101","versionType":"semver"},{"version":"6.18.25","status":"affected","lessThan":"6.18.42","versionType":"semver"},{"version":"7.0.2","status":"affected","lessThan":"7.1","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smbacl.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"6.1.184","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smbacl.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/8f3a7a499a7d9bb1c0f33fe78c4a4594d7e307f4"},{"url":"https://git.kernel.org/stable/c/f4fcd0c1a243d449307b887fafee23921e9db5ab"},{"url":"https://git.kernel.org/stable/c/0bf38372821b1526f31538a7d9811844c55c7f38"},{"url":"https://git.kernel.org/stable/c/847ecd4eb3c117c3d2f13f1e7ab506543aad8183"},{"url":"https://git.kernel.org/stable/c/bc90144ce8bb7fcf05ad9417c7adb4e9509d9e13"},{"url":"https://git.kernel.org/stable/c/bbf0a8e931204ecdab494a88d43b0a24a04285c5"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-23T12:45:49.075Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.175","versionEndExcluding":"6.1.184"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.136","versionEndExcluding":"6.6.148"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.84","versionEndExcluding":"6.12.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18.25","versionEndExcluding":"6.18.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.1.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}