This USN-8621-1 advisory details multiple Samba vulnerabilities, including a local DoS via pam_winbind (CVE-2026-15779, CVSS 6.1), several remote DoS flaws in TSIG, TKEY, and CTDB handling, and authenticated threats such as domain takeover via LDAP special directory names and information disclosure via LDAP Compare requests. Specific affected and fixed version numbers are not provided in the source material. IT security professionals should prioritize patching Samba servers according to vendor guidance.
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)