CVE-2026-53390

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An out-of-bounds read exists in the ksmbd component. The smb check perm dacl() function fails to verify if the ace->size is sufficient to contain the number of sub-authorities specified by num subauth before they are dereferenced by the compare sids() function. An authenticated client can exploit this by using SMB2 SET INFO to store a crafted Access Control Entry (ACE) with a small size but a high num subauth value in the security.NTACL extended attribute. When a subsequent SMB2 CREATE access check occurs, the system performs a heap out-of-bounds read of up to SID MAX SUB AUTHORITIES * sizeof( le32) bytes beyond the allocated buffer.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.