CVE-2026-58218
MediumCVSS 5.3Exploitation Probability (EPSS)
Elevated risk62th percentile - higher than 62% of all known CVEs
Summary
A flaw in Samba's internal DNS server allows unauthenticated TKEY registration requests to be added to the TKEY name cache before being rejected. A remote, unauthenticated attacker can send a large number of TKEY requests with arbitrary names, exhausting the cache and evicting legitimate TKEY entries.
Risk Assessment
This can prevent legitimate TSIG authentication for signed DNS queries, resulting in a denial of service (DoS) and disruption of the organization's DNS infrastructure.
Recommendation
Immediately update Samba to a patched version that fixes this vulnerability and consider restricting DNS server access to trusted networks only.
Other vulnerabilities in Samba
See all- CVE-2026-58222High
A vulnerability in Samba Active Directory Domain Controller (AD DC) combines LDAP filter injection with improper authorization checks, allowing an authenticated low-privilege domain user to disclose confidential AD attributes such as msKds-RootKeyData, potentially leading to privilege escalation and full domain compromise.
- CVE-2017-15275High
Samba before 4.7.3 might allow remote attackers to obtain sensitive information by leveraging failure of the server to clear allocated heap memory.
- CVE-2016-2119High
In Samba library versions 4.x before 4.2.14, 4.3.x before 4.3.11, and 4.4.x before 4.4.5, a vulnerability allows man-in-the-middle attackers to bypass a client-signing protection mechanism. This enables spoofing of SMB2 and SMB3 servers.
- CVE-2016-2113High
Samba versions 4.x before 4.2.11, 4.3.x before 4.3.8, and 4.4.x before 4.4.2 do not verify X.509 certificates from TLS servers, allowing man-in-the-middle attackers to spoof LDAPS and HTTPS servers and obtain sensitive information via a crafted certificate.
- CVE-2015-8467High
The samldb_check_user_account_control_acl function in Samba 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3 does not properly check for administrative privileges during the creation of machine accounts. This allows remote authenticated users to bypass intended access restrictions.
- CVE-2015-5252High
In Samba versions 3.x and 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3, a vulnerability allows remote attackers to bypass intended file-access restrictions via a symlink pointing outside of a share when certain substring relationships in share names exist.
- CVE-2015-0240High
The Netlogon server implementation in smbd in Samba 3.5.x and 3.6.x before 3.6.25, 4.0.x before 4.0.25, 4.1.x before 4.1.17, and 4.2.x before 4.2.0rc5 performs a free operation on an uninitialized stack pointer, allowing remote attackers to execute arbitrary code via crafted Netlogon packets.
- CVE-2014-8143High
Samba versions 4.0.x before 4.0.24, 4.1.x before 4.1.16, and 4.2.x before 4.2rc4, when an Active Directory Domain Controller (AD DC) is configured, allow remote authenticated users to set the LDB userAccountControl UF_SERVER_TRUST_ACCOUNT bit, consequently gaining privileges.
- CVE-2026-58221Medium
A low-privilege authenticated Samba AD user can modify internal LDB special DNs via LDAP access, enabling a domain takeover.
- CVE-2026-4408Critical
A flaw in Samba allows remote command execution due to improper escaping of shell meta-characters in the 'check password script' feature when using the %u substitution. This affects non-standard configurations with samba-dcerpcd running as a system service.
Original NVD description (English source)
A flaw was found in Samba's internal DNS server where unauthenticated TKEY registration requests were added to the TKEY name cache before being rejected. A remote, unauthenticated attacker can exploit this behavior by sending a large number of TKEY requests with arbitrary names, exhausting the cache and evicting legitimate TKEY entries. This can prevent legitimate TSIG authentication for signed DNS queries, resulting in a denial of service.