Skip to content
Ubuntu Samba Critical Denial Of Service Vulnerabilities USN-8621

Ubuntu Samba Critical Denial Of Service Vulnerabilities USN-8621

Linuxsecurity •LinuxSecurity Advisories • July 28, 2026

Audit Linux privileges now to limit compromise, escalation, and system-wide damage. Review Linux Privileges ×

Several security issues were fixed in Samba. Software Description: - samba: SMB/CIFS file, print, and login server for Unix Details: It was discovered that Samba's pam_winbind incorrectly handled directory ownership when mkhomedir was enabled. A local attacker could possibly use this issue to cause a denial of service by triggering a change in ownership of the root directory. (CVE-2026-15779) Arjun Basnet, Douglas Bagnall, and Andrew Tridgell discovered that Samba incorrectly handled TSIG packets with name compression. A remote attacker could possibly use this issue to cause Samba to crash, resulting in a denial of service. (CVE-2026-6949) Tristan Madani discovered that Samba incorrectly handled malformed ASN.1 kpasswd packets. An authenticated user could possibly use this issue to cause Samba to crash, resulting in a denial of service. (CVE-2026-58216) Andrew Tridgell and Tristan Madani discovered that Samba incorrectly handled TKEY name registration. A remote attacker ... Read the Full Advisory

Several security issues were fixed in Samba.

Software Description:

- samba: SMB/CIFS file, print, and login server for Unix

It was discovered that Samba's pam_winbind incorrectly handled

directory ownership when mkhomedir was enabled. A local attacker could

possibly use this issue to cause a denial of service by triggering a change

in ownership of the root directory. (CVE-2026-15779)

Arjun Basnet, Douglas Bagnall, and Andrew Tridgell discovered that Samba

incorrectly handled TSIG packets with name compression. A remote attacker

could possibly use this issue to cause Samba to crash, resulting in a

denial of service. (CVE-2026-6949)

Tristan Madani discovered that Samba incorrectly handled malformed ASN.1

kpasswd packets. An authenticated user could possibly use this issue to

cause Samba to crash, resulting in a denial of service. (CVE-2026-58216)

Andrew Tridgell and Tristan Madani discovered that Samba incorrectly

handled TKEY name registration. A remote attacker ...

The problem can be corrected by updating your system to the following package versions: Ubuntu 26.04 LTS samba 2:4.23.6+dfsg-1ubuntu2.2 Ubuntu 24.04 LTS samba 2:4.19.5+dfsg-4ubuntu9.7 Ubuntu 22.04 LTS samba 2:4.15.13+dfsg-0ubuntu1.13 In general, a standard system update will make all the necessary changes.

CVE-2026-15779, CVE-2026-58216, CVE-2026-58218, CVE-2026-58221,

CVE-2026-58222, CVE-2026-58224, CVE-2026-6949

Ubuntu Security Notice USN-8621-1

Get the latest Linux and open source security news straight to your inbox.