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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()… (CVE-2026-90153)

0
High
Published: 09/17/2026 (09/17/2026, 18:31:52 UTC)
Source: GCVE Database

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

CVSS v3.1

Score 8.1high

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Technical Details

Gcve Source
db.gcve.eu
Osv Id
GHSA-wffx-7972-vw67
Osv Schema Version
1.4.0
Aliases
["CVE-2026-90153"]
Database Specific Severity
HIGH
Cvss Version
3.1

Threat ID: 6aade52355bf5e2cf5edc19a

Added to database: 09/19/2026, 01:28:03 UTC

Last updated: 09/19/2026, 01:28:03 UTC

Views: 1

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