CVE-2026-90153ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size smb_check_perm_dacl() validates that the DACL fits inside the NT security descriptor, but then bounds its two ACE walks by the remaining NTSD length (acl_size) rather than the DACL's declared size (pdacl_size). When pdacl->size is smaller than the trailing NTSD buffer, bytes after the declared DACL boundary - still inside the stored security descriptor - are parsed as ACEs during access checks. A crafted DACL can place an access-granting ACE beyond pdacl->size, and the current code accepts it during SMB2_CREATE access validation, while parse_dacl() and smb_inherit_dacl() stop at pdacl_size. Bound both ACE walks by pdacl_size to match the DACL boundary semantics used elsewhere in the server. Validation: - semantic KUnit harness shows the post-boundary ACE is selected before the fix and rejected (EACCES) after it - linux master (7.2-rc6), x86_64
- CVSS
- 8.1 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Sep 18, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 8f0541186e9ad1b62accc9519cc2b7a7240272a7 before a2051ffe452afad52f580b85a3fd8851933b1e7c; from 8f0541186e9ad1b62accc9519cc2b7a7240272a7 before a29f57a14c939586d84d7fd6a029bd1fd170098f; from 8f0541186e9ad1b62accc9519cc2b7a7240272a7 before a4a307d149327dad5fb25187e1b03cebd1b04de6; 8f0541186e9ad1b62accc9519cc2b7a7240272a7 builds before 8e4f75e979c1d9a51b0a48ac33d0cfd5f039ec67; from 8f0541186e9ad1b62accc9519cc2b7a7240272a7 before 79decd88dd3f0d42e7fb0689b1a7853bfa302459; cb69d4d6f709f87c94afa28ae64c501576692171; 6e8f4abf584253cbaa596ea4ad13110cf61cd4c9; 8e33102309bd6839b2e2e158f93a7b378cb4655d; and 3 more ranges | CNA record |
References
- https://git.kernel.org/stable/c/a2051ffe452afad52f580b85a3fd8851933b1e7c
- https://git.kernel.org/stable/c/a29f57a14c939586d84d7fd6a029bd1fd170098f
- https://git.kernel.org/stable/c/a4a307d149327dad5fb25187e1b03cebd1b04de6
- https://git.kernel.org/stable/c/8e4f75e979c1d9a51b0a48ac33d0cfd5f039ec67
- https://git.kernel.org/stable/c/79decd88dd3f0d42e7fb0689b1a7853bfa302459
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.