SB2026072090 - Out-of-bounds read in Linux kernel smb server
Published: July 20, 2026
Security Bulletin ID
SB2026072090
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Out-of-bounds read (CVE-ID: CVE-2026-64138)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to an out-of-bounds read in the ksmbd smbacl.c ACL inheritance logic when processing owner and group SIDs from a parent security descriptor. A remote user can provide a specially crafted parent security descriptor to cause a denial of service.
The issue occurs during ACL inheritance in ksmbd.
Remediation
Install update from vendor's website.