CVE-2023-20080: Cisco IOS and IOS XE Software IPv6 DHCP (DHCPv6) Relay and Server Denial of Service Vulnerability

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-03-23 · updated 2026-06-17
Weakness: CWE-129

Description

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.

Affected products

Cisco IOS: 12.2(6)i1, 15.1(2)sg, 15.1(2)sg1, 15.1(2)sg2, 15.1(2)sg3, 15.1(2)sg4 (+481)
Cisco IOS XE: 3.3.0xo, 3.3.1xo, 3.3.2xo, 3.4.0sg, 3.4.1sg, 3.4.2sg (+359)

References

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