CVE-2026-93282

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: fix maximum allowed access checks

The DACL permission check looks for an ACE matching the current user and

falls back to the Everyone ACE. It does not consider an Authenticated

Users ACE, even though an authenticated session is a member of that

well-known group.

As a result, opening a file whose access is granted through S-1-5-11 can

incorrectly fail with STATUS_ACCESS_DENIED. Treat an Authenticated Users

ACE as a fallback entry alongside Everyone.

The maximal access calculation also combines access masks from every ACE,

regardless of whether its SID applies to the current user. This can grant

rights belonging to an unrelated principal. Process only ACEs applying to

the user, Everyone, or Authenticated Users, and accumulate allowed and

denied masks in ACL order. Preserve explicitly requested access bits so

they are validated against the resulting maximal mask.

When ACCESS_SYSTEM_SECURITY is denied, report S

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References