What’s Vulnerable › Vulnerabilities

CVE-2023-20051: Cisco Packet Data Network Gateway IPsec ICMP Denial of Service Vulnerability

• Severity: high (CVSS 7.5 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: 2023-04-05 · updated 2026-06-17
• Weakness: CWE-400

Description

A vulnerability in the Vector Packet Processor (VPP) of Cisco Packet Data Network Gateway (PGW) could allow an unauthenticated, remote attacker to stop ICMP traffic from being processed over an IPsec connection. This vulnerability is due to the VPP improperly handling a malformed packet. An attacker could exploit this vulnerability by sending a malformed Encapsulating Security Payload (ESP) packet over an IPsec connection. A successful exploit could allow the attacker to stop ICMP traffic over an IPsec connection and cause a denial of service (DoS).

Affected products

• Cisco Packet Data Network Gateway: before 21.28.0 — fixed in 21.28.0

How to fix

Upgrade to a fixed version: Cisco Packet Data Network Gateway 21.28.0. Check the vendor advisory for mitigations.

References

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cisco-pdng-dos-KmzwEy2Q
• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cisco-pdng-dos-KmzwEy2Q

Get alerted when CVE-2023-20051 or the next vulnerability affects your stack