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

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-11-27 · updated 2026-06-17
Weakness: CWE-617

Description

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.

Affected products

Red Hat Enterprise Linux: 9.0
[UNKNOWN] libnbd: from 1.17.4 before 1.18.2; 1.19.1 — fixed in 1.18.2

How to fix

Upgrade to a fixed version: [UNKNOWN] libnbd 1.18.2. Check the vendor advisory for mitigations.

References

https://access.redhat.com/errata/RHSA-2024:2204
https://access.redhat.com/security/cve/CVE-2023-5871
https://bugzilla.redhat.com/show_bug.cgi?id=2247308
https://lists.libguestfs.org/archives/list/guestfs@lists.libguestfs.org/thread/PFVUCMPFQUDC23JXSCUUPXIGDZ7XCFMD/
https://access.redhat.com/errata/RHSA-2024:2204
https://access.redhat.com/security/cve/CVE-2023-5871
https://bugzilla.redhat.com/show_bug.cgi?id=2247308
https://lists.libguestfs.org/archives/list/guestfs@lists.libguestfs.org/thread/PFVUCMPFQUDC23JXSCUUPXIGDZ7XCFMD/

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