CVE DATABASE / CVE-2020-3566
CVE-2020-3566
Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability
Confirmed exploited in the wild. Added 2021-11-03.
Federal remediation due 2022-05-03.
Required action: Apply updates per vendor instructions.
Summary
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 breakdown
| Base score | 8.6 (HIGH) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
| Attack vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | CHANGED |
| Confidentiality | NONE |
| Integrity | NONE |
| Availability | HIGH |
Weakness type (CWE)
Affected products
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References
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dvmrp-memexh-dSmpdvfz
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-3566
Data: NIST NVD + CISA KEV. NVD last modified 2025-10-28. Always verify against the vendor advisory before acting.