CVE-2020-3566 — Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability
Overview
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.
Vulnerability details
- CVE ID
- CVE-2020-3566
- Vulnerability
- Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability
- Vendor
- Cisco
- Affected products
- Cisco: IOS XR
- Severity
- HIGH
- Exploitation status
- Actively exploited in the wild (CISA KEV)
- Published
- 2021-11-03
Remediation guidance
CVE-2020-3566 is in CISA's Known Exploited Vulnerabilities (KEV) catalog — U.S. federal civilian agencies are required to remediate it under Binding Operational Directive 22-01. Treat it as a priority for every environment.
Apply the vendor's official security update for Cisco the affected product as soon as possible. Where a patch is unavailable, apply vendor mitigations or isolate/segment exposed systems.
Hunt for indicators of compromise tied to this vulnerability and confirm logging/EDR coverage on affected assets.
Authoritative references
Remediate CVE-2020-3566 — and stay ahead of the next one
CVE-2020-3566 is listed in the CISA KEV catalog as actively exploited — treat remediation as urgent. Scan your domain free to see whether CVE-2020-3566 and other Cisco issues affect you and get a prioritized remediation report (full report from ₹999) — or stream the full feed of 1,600+ actively-exploited CVEs straight into your SOC.
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