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CVE PROGRAM SOURCE RECORD8.1 High

CVE-2026-90153

ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size

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Status
Published
Published
Updated
Assigning organization
Linux

Description

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

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 8f0541186e9ad1b62accc9519cc2b7a7240272a7 to < a2051ffe452afad52f580b85a3fd8851933b1e7caffected
  • 8f0541186e9ad1b62accc9519cc2b7a7240272a7 to < a29f57a14c939586d84d7fd6a029bd1fd170098faffected
  • 8f0541186e9ad1b62accc9519cc2b7a7240272a7 to < a4a307d149327dad5fb25187e1b03cebd1b04de6affected
  • 8f0541186e9ad1b62accc9519cc2b7a7240272a7 to < 8e4f75e979c1d9a51b0a48ac33d0cfd5f039ec67affected
  • 8f0541186e9ad1b62accc9519cc2b7a7240272a7 to < 79decd88dd3f0d42e7fb0689b1a7853bfa302459affected
  • cb69d4d6f709f87c94afa28ae64c501576692171affected
  • 6e8f4abf584253cbaa596ea4ad13110cf61cd4c9affected
  • 8e33102309bd6839b2e2e158f93a7b378cb4655daffected
  • 5.15.62 to < 5.16affected
  • 5.18.18 to < 5.19affected
  • 5.19.2 to < 5.20affected

Linux Linux

Default version status: affected

  • 6.0affected
  • 0 to < 6.0unaffected
  • 6.6.157 to ≤ 6.6.*unaffected
  • 6.12.110 to ≤ 6.12.*unaffected
  • 6.18.52 to ≤ 6.18.*unaffected
  • 7.2.6 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References