The ownerset function in smbcacls.c in smbcacls in Samba 4.0.x before 4.0.16 and 4.1.x before 4.1.6 removes an ACL during use of a --chown or --chgrp option, which allows remote attackers to bypass intended access restrictions in opportunistic circumstances by leveraging an unintended administrative change.
Samba 3.x before 3.6.23, 4.0.x before 4.0.16, and 4.1.x before 4.1.6 does not enforce the password-guessing protection mechanism for all interfaces, which makes it easier for remote attackers to obtain access via brute-force ChangePasswordUser2 (1) SAMR or (2) RAP attempts.
The internal DNS server in Samba 4.x before 4.0.18 does not check the QR field in the header section of an incoming DNS message before sending a response, which allows remote attackers to cause a denial of service (CPU and bandwidth consumption) via a forged response packet that triggers a communication loop, a related issue to CVE-1999-0103.
Samba 3.6.6 through 3.6.23, 4.0.x before 4.0.18, and 4.1.x before 4.1.8, when a certain vfs shadow copy configuration is enabled, does not properly initialize the SRVSNAPSHOTARRAY response field, which allows remote authenticated users to obtain potentially sensitive information from process memory via a (1) FSCTLGETSHADOWCOPYDATA or (2) FSCTLSRVENUMERATESNAPSHOTS request.
Last updated 18 August 2025
All Samba versions 4.x.x before 4.9.17, 4.10.x before 4.10.11 and 4.11.x before 4.11.3 have an issue, where the S4U (MS-SFU) Kerberos delegation model includes a feature allowing for a subset of clients to be opted out of constrained delegation in any way, either S4U2Self or regular Kerberos authentication, by forcing all tickets for these clients to be non-forwardable. In AD this is implemented by a user attribute delegationnotallowed (aka not-delegated), which translates to disallow-forwardable. However the Samba AD DC does not do that for S4U2Self and does set the forwardable flag even if the impersonated client has the not-delegated flag set.
All Samba versions 4.x.x before 4.9.17, 4.10.x before 4.10.11 and 4.11.x before 4.11.3 have an issue, where the (poorly named) dnsserver RPC pipe provides administrative facilities to modify DNS records and zones. Samba, when acting as an AD DC, stores DNS records in LDAP. In AD, the default permissions on the DNS partition allow creation of new records by authenticated users. This is used for example to allow machines to self-register in DNS. If a DNS record was created that case-insensitively matched the name of the zone, the ldbqsort() and dnsnamecompare() routines could be confused into reading memory prior to the list of DNS entries when responding to DnssrvEnumRecords() or DnssrvEnumRecords2() and so following invalid memory as a pointer.
As per samba upstream advisory:
On a Samba 4 AD DC the LDAP server in all versions of Samba from 4.0.0 onwards incorrectly validates permissions to modify passwords over LDAP allowing authenticated users to change any other users passwords, including administrative users.
Last updated 25 August 2025
A denial of service vulnerability was discovered in Samba's LDAP server before versions 4.7.12, 4.8.7, and 4.9.3. A CNAME loop could lead to infinite recursion in the server. An unprivileged local attacker could create such an entry, leading to denial of service.
Last updated 25 August 2025
An integer overflow flaw was found in the way samba read an EA list provided by the client. A malicious client could send a specially crafted EA list that wraps perfectly on a 32-bit boundary, causing the server to loop and re-process the list. This can cause Denial of Service via memory exhaustion.
Reference:
https://bugzilla.samba.org/showbug.cgi?id=10010 (curently private)
A flaw was found in all Samba versions before 4.10.17, before 4.11.11 and before 4.12.4 in the way it processed NetBios over TCP/IP. This flaw allows a remote attacker could to cause the Samba server to consume excessive CPU use, resulting in a denial of service. This highest threat from this vulnerability is to system availability.