CVE-2023-42670VulnerabilityPublished 3 Nov 2023Updated 20 Nov 2025

CVE-2023-42670: samba · Uncontrolled Resource Consumption

Affects sambaSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 07:57 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 1.3% chance of exploitation in 30 days – higher than 70% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Nov 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Red Hatredhat/samba`pkg:rpm/redhat/samba`Other threats	Affected =4.16.0 =4.18.0 =4.19.0	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2023-42670, organizations should first identify if they are running affected Samba versions (4.16.0, 4.18.0, 4.19.0) especially in AD DC or NT4-emulation roles. Immediate steps include applying vendor patches or updates as they become available. In the absence of patches, administrators should monitor RPC server load and responsiveness closely to detect abnormal behavior that could trigger multiple RPC listeners. Restricting access to Samba RPC services to trusted hosts and networks can reduce exploitation risk. Implementing strict privilege management to limit who can interact with Samba RPC services is critical since the attack requires some level of privilege. Additionally, configuring Samba to disable NT4-emulation classic DC roles if not needed can prevent the conflicting server startup scenario. Regularly auditing Samba logs for unusual RPC listener activity and socket conflicts can help early detection. Network segmentation and intrusion detection systems tuned for Samba anomalies can provide further defense. Finally, ensure backup and recovery plans are in place to restore AD DC services quickly if disruption occurs.

Description

A flaw was found in Samba. It is susceptible to a vulnerability where multiple incompatible RPC listeners can be initiated, causing disruptions in the AD DC service. When Samba's RPC server experiences a high load or unresponsiveness, servers intended for non-AD DC purposes (for example, NT4-emulation "classic DCs") can erroneously start and compete for the same unix domain sockets. This issue leads to partial query responses from the AD DC, causing issues such as "The procedure number is out of range" when using tools like Active Directory Users. This flaw allows an attacker to disrupt AD DC services.

Impact

For European organizations, the disruption of AD DC services due to this vulnerability can have significant operational impacts. Active Directory is central to identity management, authentication, and authorization in many enterprises, and interruptions can lead to widespread access issues, delayed user logins, and failure of critical business applications relying on AD. Organizations using Samba as their AD DC or in NT4-emulation roles are particularly at risk. This could affect sectors with high dependency on directory services such as finance, government, healthcare, and telecommunications. The availability impact could lead to downtime, loss of productivity, and increased support costs. While no data breach or integrity compromise is indicated, the denial-of-service aspect can be exploited for targeted disruption or as part of a larger attack chain. Given the medium severity and the requirement for some privileges, insider threats or attackers who have gained limited access could exploit this vulnerability to cause service degradation.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 20 Nov 2025, 18:37 UTC

Technical details

References

Community reviews

Related threats