CVE-2020-3566
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.
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:HActively exploited. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1638 days
- CVSS
- 8.6 HIGH
- EPSS (30-day exploit probability)
- 3.7% · top 10% of all CVEs
- Weakness
- CWE-400
- Attack vector
- Network, remotely reachable
- Preconditions
- No privileges and no user interaction
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.