What is CVE-2023-20080?

CVE-2023-20080 is a high-severity vulnerability in Cisco iOS, classified under Improper Validation of Array Index. CVSS score: 8.6/10. Published 2023-03-23.

How severe is CVE-2023-20080?

High severity. CVSS v3 base score is 8.6 out of 10.

Vulnerability in Cisco iOS

CVE-2023-20080

A vulnerability in the IPv6 DHCP version 6 (DHCPv6) relay and server features of Cisco IOS and IOS XE Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to insufficient validation of data boundaries. An attacker could exploit this vulnerability by sending crafted DHCPv6 messages to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly.

Published 2023-03-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.010 (60.7th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 60.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Cisco iOS
Cisco iOS — versions 15.5\(3\)s1a, 15.5\(3\)m7, 15.2\(4\)ea5
Cisco iOS Xe — versions 3.3.0xo, 3.3.1xo, 3.3.2xo

Weakness classification (CWE)

CWE-129 — Improper Validation of Array Index

References

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-… (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2023-20080?: CVE-2023-20080 is a high-severity vulnerability in Cisco iOS, classified under Improper Validation of Array Index. CVSS score: 8.6/10. Published 2023-03-23.
How severe is CVE-2023-20080?: High severity. CVSS v3 base score is 8.6 out of 10.