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CVE-2020-3566

67
FAUCET Score

CVE-2020-3566 is a critical vulnerability in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software, affecting various ASR 9000 series routers. An unauthenticated, remote attacker can exploit insufficient queue management for IGMP packets by sending crafted traffic, leading to memory exhaustion and instability of critical processes. With a CVSS score of 8.6 (HIGH) and a FAUCET Risk Score of 99/100, this vulnerability has a severe impact on availability. It is actively exploited in the wild, as confirmed by its presence in the KEV catalog and extensive media coverage, despite a lack of public exploit code in Metasploit or ExploitDB. The vulnerability has garnered significant community discussion, indicating high awareness.

Impacted Technologies

VendorProductVersion(s)CPE
6.4.2CPE matchmatch criteria
cpe:2.3:o:cisco:ios_xr:6.4.2:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.6HIGH

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 Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
4.0
CvssVersion
3.1

Exploit Intelligence

EPSS Score
3.63%
Probability of exploitation in next 30 days
EPSS Percentile
88.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
Added to KEV · Nov 3, 2021
This CVE's current EPSS score of 0.0363 is in the 79th percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (1)

ciscovendor investigatingvia nvd_reference
View patch

References

cisa.gov / known-exploited-vulnerabilities-catalog
US Government Resource
tools.cisco.com / security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dvmrp-memexh-dSmpdvfz
Vendor Advisory