CVE-2020-3566

highpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.037 · 90 %ileEURUUS

grimoire priorityP0 · Act now

Exploitable?

Yes · in the wild

CISA KEV

Likely / severe?

3.70% (90th) EPSS

CVSS 7.8 · high

Is it mine?

34 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · cisco_csaf

added 2021-11-03remediate by 2022-05-03

required action Apply updates per vendor instructions.

EPSS · scored 2026-10-23

Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability

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.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedCisco IOS XR Softwarecisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com

cvss

Technical severity, 0–10. One row per scoring source.

8.6

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.07.8highAV:N/AC:L/Au:N/C:N/I:N/A:Cprimary · NVD / NIST USexploitability 10 · impact 6.9

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 4

v3.18.6highAV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · psirt@cisco.com USexploitability 3.9 · impact 4

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:Hsecondary · CVSS-BT (t0sche)

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · Cisco PSIRT US

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: active · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-770USprimaryCWE-400USCWE-400US

affected products (34)

Products and version ranges known to be affected.

Cisco Cisco IOS XR Softwareall versionscisco_csafUS
Cisco Cisco IOS XR Software≤ n/aenisa_euvdEU
Cisco Systems Inc. Cisco ASR 9000 Series Aggregation Services Routers≤ 7.0fstec_bduRU
Cisco Systems Inc. Cisco ASR 9000 Series Aggregation Services Routers≤ 6.6.3fstec_bduRU
Cisco Systems Inc. Cisco ASR 9000 Series Aggregation Services Routers≤ 6.6fstec_bduRU
Cisco Systems Inc. Cisco ASR 9000 Series Aggregation Services Routers≤ 6.4.2fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 7.3.1fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 7.2.1fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 7.1.2fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 6.6.3fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 6.5.3fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 6.5.2fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 6.4.3fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 6.4.2fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 6.4.1fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 6.3.15fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 6.3.3fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 6.2.25fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 6.2.3fstec_bduRU
Cisco Systems Inc. Cisco IOS XR≤ 6.2.1fstec_bduRU

showing 20 of 34

advisories (1)

Vendor and ecosystem advisories describing this.

cisco-sa-iosxr-dvmrp-memexh-dSmpdvfzCisco IOS XR Software DVMRP Memory Exhaustion Vulnerabilities2020-08-29csaf · cisco_csafUS
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 has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities. There are multiple mitigations available to customers depending on their needs.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cisco_csaf NVD CVE.org MITRE

published 2020-08-29modified 2026-06-17

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references (12)

External citations — patches, advisories, analysis.

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