What is CVE-2021-38598?

CVE-2021-38598 is a critical-severity vulnerability in OpenStack Neutron, classified under Authentication Bypass by Spoofing. CVSS score: 9.1/10. Published 2021-08-23.

How severe is CVE-2021-38598?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Vulnerability in OpenStack Neutron

CVE-2021-38598

OpenStack Neutron before 16.4.1, 17.x before 17.1.3, and 18.0.0 allows hardware address impersonation when the linuxbridge driver with ebtables-nft is used on a Netfilter-based platform. By sending carefully crafted packets, anyone in control of a server instance connected to the virtual switch can impersonate the hardware addresses of other systems on the network, resulting in denial of service or in some cases possibly interception of traffic intended for other destinations.

Published 2021-08-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.

EPSS exploit prediction

EPSS: 0.012 (68.2th percentile), scored 2026-10-20.

Low probability of exploitation in the next 30 days, but still tracked. 68th percentile — 68.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

OpenStack Neutron — versions 18.0.0

Weakness classification (CWE)

CWE-290 — Authentication Bypass by Spoofing

References

launchpad.net/bugs/1938670 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2021-38598?: CVE-2021-38598 is a critical-severity vulnerability in OpenStack Neutron, classified under Authentication Bypass by Spoofing. CVSS score: 9.1/10. Published 2021-08-23.
How severe is CVE-2021-38598?: Critical severity. CVSS v3 base score is 9.1 out of 10.