CVE-2021-38598

Exp

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 update: 2024-11-21 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2021-38598 is rated High Exploit Risk (74.6/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.17%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +1.06% over the last day, indicating growing attacker interest. Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-38598

EDB-ID Source Kind Published Link
nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-38598

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.11% 1.17% +1.06%
2 2026-05-12 0.04% 0.11% +0.08%
3 2025-11-21 0.04%

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-38598

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.1 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 5.2 [email protected]
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
8.6 4.9 [email protected]

Weakness enumeration for CVE-2021-38598

GitHub Security Advisory for CVE-2021-38598

GHSA-hvm4-mc7m-22w4 · Severity: high · Ecosystem: pip — OpenStack Neutron vulnerable to hardware address impersonation

OS Trackers for CVE-2021-38598

vendor priority summary link
debian not yet assigned CVE-2021-38598 not yet assigned priority: Debian including 1 source packages (neutron), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-38598
redhat medium https://access.redhat.com/security/cve/CVE-2021-38598
suse medium CVE-2021-38598 severity moderate: SUSE including 12 source package names (openstack-neutron, openstack-neutron-dhcp-agent, …), 72 product×package rows across 6 product lines (HPE Helion OpenStack 8, SUSE OpenStack Cloud 7, … (6 product lines)): Known Not Affected 72. https://www.suse.com/security/cve/CVE-2021-38598/
ubuntu medium CVE-2021-38598 medium priority: Ubuntu including 1 source packages (neutron), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 9, released 3, DNE 1, ignored 1, needs-triage 1. https://ubuntu.com/security/CVE-2021-38598

Affected software / configurations for CVE-2021-38598

Vendor Product Version Raw CPE
openstack neutron < 16.4.1 cpe:2.3:a:openstack:neutron:*:*:*:*:*:*:*:*
openstack neutron >= 17.0.0, < 17.1.3 cpe:2.3:a:openstack:neutron:*:*:*:*:*:*:*:*
openstack neutron 18.0.0 cpe:2.3:a:openstack:neutron:18.0.0:*:*:*:*:*:*:*

References for CVE-2021-38598

URL Tags
https://launchpad.net/bugs/1938670 Exploit Issue Tracking Third Party Advisory
cvelogic Threat Intelligence