ACTIVELY EXPLOITED

CVE-2020-3569: Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability

Facts
VendorCisco
ProductIOS XR
Actively exploitedYes
Added to CISA KEV3 Nov 2021
CISA federal deadline3 May 2022
Weakness (CWE)CWE-400

Required action (CISA's text)

Apply updates per vendor instructions.

Description (NVD)

Cisco IOS XR Distance Vector Multicast Routing Protocol (DVMRP) incorrectly handles Internet Group Management Protocol (IGMP) packets. Exploitation could allow an unauthenticated, remote attacker to immediately crash the IGMP process or make it consume available memory and eventually crash.

SOURCES

Other Cisco flaws

Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.