# CVE-2023-5871: Libnbd: malicious nbd server may crash libnbd

Status: published. Published: 2023-11-27. Updated: 2026-11-05.

A flaw was found in libnbd, due to a malicious Network Block Device (NBD), a protocol for accessing Block Devices such as hard disks over a Network. This issue may allow a malicious NBD server to cause a Denial of Service.

## Remediation

- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 9 (libnbd): ≥ 0:1.18.1-3.el9; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (libnbd): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (libnbd): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (virt:rhel/libnbd): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 5.3 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 1.11% as of 2026-11-04; percentile 65.98%

- SSVC: Not available

- Weaknesses: CWE-617

## Exploit evidence

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

## References

- https://access.redhat.com/errata/RHSA-2024:2204 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2023-5871 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2247308 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://lists.libguestfs.org/archives/list/guestfs@lists.libguestfs.org/thread/PFVUCMPFQUDC23JXSCUUPXIGDZ7XCFMD/ (CNA: redhat)

- https://access.redhat.com/errata/RHSA-2024:2204 (ADP: CVE; vendor-advisory, x_refsource_REDHAT, x_transferred)

- https://access.redhat.com/security/cve/CVE-2023-5871 (ADP: CVE; vdb-entry, x_refsource_REDHAT, x_transferred)

- https://bugzilla.redhat.com/show_bug.cgi?id=2247308 (ADP: CVE; issue-tracking, x_refsource_REDHAT, x_transferred)

- https://lists.libguestfs.org/archives/list/guestfs@lists.libguestfs.org/thread/PFVUCMPFQUDC23JXSCUUPXIGDZ7XCFMD/ (ADP: CVE; x_transferred)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2023-5871; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2023-5871; retrieved 2026-11-05; source updated Not reported

Revision: bacb022debbbdd4d59e697fd7385541eb889532290c9aac8c2e7c186adddee42

Canonical: https://y2.dev/cve/CVE-2023-5871

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