Riskcovery

CVE-2026-90153

ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size

State
Published
Severity
8.1 High
Published
Sep 17, 2026
Updated
Oct 30, 2026
Reserved
Sep 11, 2026

Read the record on cve.org

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

Scores

CVSSScoreVectorSource
3.18.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:NLinux

Weaknesses

The record names no weakness.

Affected Products

ProductVersions
LinuxLinux
  • 8f0541186e9ad1b62accc9519cc2b7a7240272a7 to before 930dcdd888eabf166589e020dcbf6d15b5e13305Affected
  • 8f0541186e9ad1b62accc9519cc2b7a7240272a7 to before a2051ffe452afad52f580b85a3fd8851933b1e7cAffected
  • 8f0541186e9ad1b62accc9519cc2b7a7240272a7 to before a29f57a14c939586d84d7fd6a029bd1fd170098fAffected
  • 8f0541186e9ad1b62accc9519cc2b7a7240272a7 to before a4a307d149327dad5fb25187e1b03cebd1b04de6Affected
  • 8f0541186e9ad1b62accc9519cc2b7a7240272a7 to before 8e4f75e979c1d9a51b0a48ac33d0cfd5f039ec67Affected
  • 8f0541186e9ad1b62accc9519cc2b7a7240272a7 to before 79decd88dd3f0d42e7fb0689b1a7853bfa302459Affected
  • cb69d4d6f709f87c94afa28ae64c501576692171Affected
  • 6e8f4abf584253cbaa596ea4ad13110cf61cd4c9Affected
  • 8e33102309bd6839b2e2e158f93a7b378cb4655dAffected
  • 5.15.62 to before 5.16Affected
  • 5.18.18 to before 5.19Affected
  • 5.19.2 to before 5.20Affected
LinuxLinux
  • 6.0Affected
  • before 6.0Not affected
  • 6.1.191 through 6.1.*Not affected
  • 6.6.157 through 6.6.*Not affected
  • 6.12.110 through 6.12.*Not affected
  • 6.18.52 through 6.18.*Not affected
  • 7.2.6 through 7.2.*Not affected
  • 7.3 and laterNot affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.