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

Exp

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.

Published: 2020-09-23 Last update: 2025-10-28 Assigner: [email protected] Source: [email protected]

NVD Status：Analyzed，CVE State: published

View at NVD, CVE.org, EUVD

Threat Intelligence & Risk Assessment for CVE-2020-3569

KEV EPSS CVSS CWE Affected

Conclusion & alert: CVE-2020-3569 is rated Critical Active Threat (89.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 4.71%). Core evidence: CISA KEV confirms active exploitation (added 2021-11-03) affecting Cisco / IOS XR. a weakness (CWE-400) Unauthenticated remote administrative access may be possible. Mandatory action: The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2020-3569

Name: Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability · CISA KEV detail

Exploit added: 2021-11-03

Action due: 2022-05-03

Required action: Apply updates per vendor instructions.

Exploit prediction scoring system (EPSS) score for CVE-2020-3569

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-03-17	5.55%	4.71%	-0.84%
2	2026-02-22	16.09%	5.55%	-10.54%
3	2025-12-28	—	16.09%	—

Full EPSS history (23 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-3569

CVSS metrics for this CVE.

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.6	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	4.0	[email protected]
8.6	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	4.0	[email protected]
5.0	2.0	MEDIUM	`AV:N/AC:L/Au:N/C:N/I:N/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	10.0	2.9	[email protected]

Weakness enumeration for CVE-2020-3569

CWE-400 MITRE ↗ CWE-770 MITRE ↗

Affected software / configurations for CVE-2020-3569

Vendor	Product	Version	Raw CPE
cisco	ios_xr	6.1.4	cpe:2.3:o:cisco:ios_xr:6.1.4:::::::*
cisco	ios_xr	6.2.3	cpe:2.3:o:cisco:ios_xr:6.2.3:::::::*
cisco	ios_xr	6.3.3	cpe:2.3:o:cisco:ios_xr:6.3.3:::::::*
cisco	ios_xr	6.4.2	cpe:2.3:o:cisco:ios_xr:6.4.2:::::::*
cisco	ios_xr	6.5.3	cpe:2.3:o:cisco:ios_xr:6.5.3:::::::*
cisco	ios_xr	6.6.2	cpe:2.3:o:cisco:ios_xr:6.6.2:::::::*
cisco	ios_xr	6.6.3	cpe:2.3:o:cisco:ios_xr:6.6.3:::::::*
cisco	ios_xr	7.0.2	cpe:2.3:o:cisco:ios_xr:7.0.2:::::::*
cisco	ios_xr	7.1.2	cpe:2.3:o:cisco:ios_xr:7.1.2:::::::*
cisco	ios_xr	7.1.15	cpe:2.3:o:cisco:ios_xr:7.1.15:::::::*
cisco	ios_xr	< 6.5.2	cpe:2.3:o:cisco:ios_xr::::::::
cisco	ios_xr	6.4.3	cpe:2.3:o:cisco:ios_xr:6.4.3:::::::*

References for CVE-2020-3569

URL	Tags
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dvmrp-memexh-dSmpdvfz	Mitigation Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-3569	US Government Resource

cvelogic Threat Intelligence