High 8.6Known exploited (CISA KEV)Published Sep 23, 2020

CVE-2020-3569Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerabilities

Updated under an hour ago (2026-10-19 11:10 UTC)

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It affects Cisco IOS XR Software and 1 other product. Add what you run to find out whether that includes you.

CISA lists it as known exploited since Nov 3, 2021; federal agencies had to remediate by May 3, 2022. Treat that date as your deadline.

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Exploited in the last 30 days

Multiple vulnerabilities in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to either immediately crash the Internet Group Management Protocol (IGMP) process or make it consume available memory and eventually crash. The memory consumption may negatively impact other processes that are running on the device. These vulnerabilities are due to the incorrect handling of IGMP packets. An attacker could exploit these vulnerabilities by sending crafted IGMP traffic to an affected device. A successful exploit could allow the attacker to immediately crash the IGMP process or cause memory exhaustion, resulting in other processes becoming unstable. These processes may include, but are not limited to, interior and exterior routing protocols. Cisco will release software updates that address these vulnerabilities.

CVSS: 8.6 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Weakness (CWE): CWE-400
Known exploited: Added to CISA KEV Nov 3, 2021; federal remediation due May 3, 2022Apply updates per vendor instructions.
EPSS (exploitation in the next 30 days): 3.32% (percentile 88)
Assigned by: cisco
NVD analysis: Analyzed
Record last updated: Oct 21, 2025
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Cisco Cisco IOS XR Software cisco:ios_xr_software (from the name)	all versions	CNA record
cisco ios_xr cisco:ios_xr	6.1.4; 6.2.3; 6.3.3; 6.4.2; 6.5.3; 6.6.2; 6.6.3; 7.0.2; and 6 more ranges	NVD

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dvmrp-memexh-dSmpdvfzvendor-advisory, x-refsource-cisco, mitigation
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-3569us-government-resource

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.