========================================================================== Ubuntu Security Notice USN-8621-1 July 28, 2026
samba vulnerabilities ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 26.04 LTS - Ubuntu 24.04 LTS - Ubuntu 22.04 LTS Summary: 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 home 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 could possibly use this issue to exhaust the TKEY name cache, resulting in a denial of service. (CVE-2026-58218) It was discovered that Samba incorrectly handled internal LDB special directory names when processing authenticated LDAP requests. An authenticated user could possibly use this issue to perform unauthorized modifications and gain control of a domain. (CVE-2026-58221) Andrew Tridgell and Tristan Madani discovered that Samba incorrectly handled LDAP Compare requests. An authenticated user could possibly use this issue to obtain sensitive information. (CVE-2026-58222) Tristan Madani, Andrew Tridgell, and Martin Schwenke discovered that the CTDB protocol in Samba had insufficient bounds checking. A remote attacker could possibly use this issue to cause Samba to crash, resulting in a denial of service. (CVE-2026-58224) Update instructions: 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. References: https://ubuntu.com/security/notices/USN-8621-1 CVE-2026-15779, CVE-2026-58216, CVE-2026-58218, CVE-2026-58221, CVE-2026-58222, CVE-2026-58224, CVE-2026-6949 Package Information: https://launchpad.net/ubuntu/+source/samba/2:4.23.6+dfsg-1ubuntu2.2 https://launchpad.net/ubuntu/+source/samba/2:4.19.5+dfsg-4ubuntu9.7 https://launchpad.net/ubuntu/+source/samba/2:4.15.13+dfsg-0ubuntu1.13
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