SB2026061529 - Red Hat Enterprise Linux 9 update for samba
Published: June 15, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 5 vulnerabilities.
1) Improper access control (CVE-ID: CVE-2026-1933)
CWE-ID: CWE-284 - Improper Access Control
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote user to modify reparse point metadata on files despite read-only share restrictions.
The vulnerability exists due to improper access control in reparse point operations when handling set or delete requests for reparse point xattrs on files through a read-only share or a read-only file handle. A remote user can set or delete reparse point xattrs on files to modify reparse point metadata on files despite read-only share restrictions.
The issue occurs on shares configured with "read only = yes" and on file handles opened read-only, for files where the user has write access in the underlying file system.
2) Improper access control (CVE-ID: CVE-2026-2340)
CWE-ID: CWE-284 - Improper Access Control
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote user to overwrite protected files.
The vulnerability exists due to improper access control in the WORM vfs module when processing file rename operations. A remote user can rename a newly created file over a protected file to overwrite protected files.
3) Improper Certificate Validation (CVE-ID: CVE-2026-3012)
CWE-ID: CWE-295 - Improper Certificate Validation
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to compromise certificate trust during auto-enrolment.
The vulnerability exists due to improper certificate validation in auto-enrolment GPO certificate installation when fetching a CA certificate over HTTP without verification. A remote attacker can tamper with the certificate retrieval process to compromise certificate trust during auto-enrolment.
The issue arises because HTTP was trusted for bootstrapping a certificate chain even when a more secure encrypted LDAP channel was available.
4) Command injection (CVE-ID: CVE-2026-4480)
CWE-ID: CWE-77 - Command injection
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to command injection in the Samba printing subsystem when invoking a print command that uses the %J substitution character. A remote attacker can submit crafted print job data that reaches the print command to execute arbitrary code.
Exploitation requires a Samba print server with a configured "print command" that uses the %J substitution character.
5) Command injection (CVE-ID: CVE-2026-4408)
CWE-ID: CWE-77 - Command injection
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to command injection in the Samba DCE/RPC SAMR server when invoking a check password script that uses the %u substitution character. A remote attacker can send crafted input that reaches the check password script to execute arbitrary code.
Exploitation requires samba-dcerpcd to be started as a system service on Samba file servers or classic non-AD domain controllers, and requires a configured "check password script" that uses the %u substitution character.
Remediation
Install update from vendor's website.