Cisco · IOS XR
CVE-2020-3566
Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability
What it is
A vulnerability in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to exhaust process memory of an affected device. The vulnerability is due to insufficient queue management for Internet Group Management Protocol (IGMP) packets. An attacker could exploit this vulnerability by sending crafted IGMP traffic to an affected device. A successful exploit could allow the attacker to cause memory exhaustion, resulting in instability of other processes. These processes may include, but are not limited to, interior and exterior routing protocols. Cisco will release software updates that address this vulnerability.
CISA: 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.
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: May 3, 2022
More exploited flaws from Cisco
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| May 23, 2022 | Open Port | IOS XR | Medium 6.5 | 11% |
| Mar 25, 2022 | Border Gateway Protocol (BGP) Denial-of-Service | IOS XR | Medium 5.9 | 3.3% |
| Mar 25, 2022 | Border Gateway Protocol (BGP) Denial-of-Service | IOS XR | High 7.5 | 5.7% |
| Nov 3, 2021 | Software Discovery Protocol Format String | IOS XR | High 8.8 | 12% |
| Nov 3, 2021 | Software DVMRP Memory Exhaustion | IOS XR | High 8.6 | 3.3% |
| Oct 14, 2026 | Relative Path Traversal | Secure Email Gateway | Critical 9.8 | 2.2% |
| Sep 30, 2026 | Hex Encoding | Catalyst SD-WAN Manager | Critical 9.8 | 39% |
| Sep 16, 2026 | Incorrect Use of Privileged APIs | Identity Services Engine | Critical 10.0 | 76% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.