# CVE-2023-42670: Samba: ad dc busy rpc multiple listener dos

Status: published. Published: 2023-11-03. Updated: 2026-11-07.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

-  /  (samba): ≥ 4.16.0; < 4.17.12 (affected, semver); ≥ 4.18.0; < 4.18.8 (affected, semver); 4.19.0 (affected). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (samba): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (samba4): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (samba): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (samba): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (samba): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Storage 3 (samba): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 1.32% as of 2026-11-06; percentile 70.92%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-400

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/security/cve/CVE-2023-42670 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2241885 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://bugzilla.samba.org/show_bug.cgi?id=15473 (CNA: redhat)

- https://www.samba.org/samba/security/CVE-2023-42670.html (CNA: redhat)

- https://access.redhat.com/security/cve/CVE-2023-42670 (ADP: CVE; vdb-entry, x_refsource_REDHAT, x_transferred)

- https://bugzilla.redhat.com/show_bug.cgi?id=2241885 (ADP: CVE; issue-tracking, x_refsource_REDHAT, x_transferred)

- https://bugzilla.samba.org/show_bug.cgi?id=15473 (ADP: CVE; x_transferred)

- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZUMVALLFFDFC53JZMUWA6HPD7HUGAP5I/ (ADP: CVE; x_transferred)

- https://security.netapp.com/advisory/ntap-20231124-0002/ (ADP: CVE; x_transferred)

- https://www.samba.org/samba/security/CVE-2023-42670.html (ADP: CVE; x_transferred)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2023-42670; retrieved 2026-11-07; source updated 2026-11-07

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2023-42670; retrieved 2026-11-07; source updated Not reported

Revision: ec53bb892863295b3222e27f39f7f23ac38b86dadf482387f88a650a94e97327

Canonical: https://y2.dev/cve/CVE-2023-42670

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