AZL-102458
See a problem?- Import Source
- https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-102458.json
- JSON Data
- https://api.osv.dev/v1/vulns/AZL-102458
- Upstream
- Published
- 2026-09-17T17:17:08Z
- Modified
- 2026-09-18T14:16:33Z
- Summary
- CVE-2026-90153 affecting package kernel 6.6.150.1-1
- Details
-
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
- References