{"id":"CVE-2026-90153","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: bound smb_check_perm_dacl() ACE walks by DACL size\n\nsmb_check_perm_dacl() validates that the DACL fits inside the NT\nsecurity descriptor, but then bounds its two…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: bound smb_check_perm_dacl() ACE walks by DACL size\n\nsmb_check_perm_dacl() validates that the DACL fits inside the NT\nsecurity descriptor, but then bounds its two…","severity":"high","cvss":8.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","vendor":"Linux","product":"Linux","affected":["Linux >= 8f0541186e9ad1b62accc9519cc2b7a7240272a7 < a2051ffe452afad52f580b85a3fd8851933b1e7c","Linux >= 8f0541186e9ad1b62accc9519cc2b7a7240272a7 < a29f57a14c939586d84d7fd6a029bd1fd170098f","Linux >= 8f0541186e9ad1b62accc9519cc2b7a7240272a7 < a4a307d149327dad5fb25187e1b03cebd1b04de6","Linux >= 8f0541186e9ad1b62accc9519cc2b7a7240272a7 < 8e4f75e979c1d9a51b0a48ac33d0cfd5f039ec67","Linux >= 8f0541186e9ad1b62accc9519cc2b7a7240272a7 < 79decd88dd3f0d42e7fb0689b1a7853bfa302459","Linux cb69d4d6f709f87c94afa28ae64c501576692171","Linux 6e8f4abf584253cbaa596ea4ad13110cf61cd4c9","Linux 8e33102309bd6839b2e2e158f93a7b378cb4655d","Linux >= 5.15.62 < 5.16","Linux >= 5.18.18 < 5.19","Linux >= 5.19.2 < 5.20","Linux 6.0"],"published":"2026-09-17","updated":"2026-09-18","sourceUpdated":"2026-09-18T18:17:44.427","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90153","references":[{"url":"https://git.kernel.org/stable/c/79decd88dd3f0d42e7fb0689b1a7853bfa302459","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8e4f75e979c1d9a51b0a48ac33d0cfd5f039ec67","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a2051ffe452afad52f580b85a3fd8851933b1e7c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a29f57a14c939586d84d7fd6a029bd1fd170098f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a4a307d149327dad5fb25187e1b03cebd1b04de6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"epss":0.00445,"epssPercentile":0.38008,"ingestedAt":"2026-09-17T16:21:47.874Z","slug":"CVE-2026-90153","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: bound smb_check_perm_dacl() ACE walks by DACL size\n\nsmb_check_perm_dacl() validates that the DACL fits inside the NT\nsecurity descriptor, but then bounds its two ACE walks by the\nremaining NTSD length (acl_size) rather than the DACL's declared\nsize (pdacl_size).\n\nWhen pdacl->size is smaller than the trailing NTSD buffer, bytes\nafter the declared DACL boundary - still inside the stored security\ndescriptor - are parsed as ACEs during access checks.  A crafted\nDACL can place an access-granting ACE beyond pdacl->size, and the\ncurrent code accepts it during SMB2_CREATE access validation, while\nparse_dacl() and smb_inherit_dacl() stop at pdacl_size.\n\nBound both ACE walks by pdacl_size to match the DACL boundary\nsemantics used elsewhere in the server.\n\nValidation:\n- semantic KUnit harness shows the post-boundary ACE is selected\n  before the fix and rejected (EACCES) after it\n- linux master (7.2-rc6), x86_64\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":44.6,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":207153,"id":"CVE-2026-90153","ts":1789757336492,"field":"cvss","old":null,"new":"8.1"},{"seq":207152,"id":"CVE-2026-90153","ts":1789757336492,"field":"severity","old":"none","new":"high"}]}