CASCACascade Atlas

Evidence dossier

CVE-2020-3566

Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability

63.3–80.3Priority evidence range
As known Jul 19, 2026, 5:00 AM UTCgen-56ccdaf9

Normalized restatement

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.

State
PUBLISHED
Published
Aug 29, 2020
Updated
Oct 21, 2025
Evidence coverage
85%
CISA KEVCatalog member

Apply updates per vendor instructions.

FIRST EPSS3.63%

2026-07-18 · v2026.06.15 · percentile 88.3%

Source stateNo scored conflict

Distinct CVSS assessments remain side by side; none are averaged.

Source comparison

Who said what

CISA-ADPindependent enrichment
container

CISA ADP Vulnrichment

ciscooriginal assertion
container

Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability

CVEderivative copy
container

CVE Program Container

CISA KEVoriginal assertion
observed_exploitation

Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability

FIRST EPSSoriginal assertion
model_probability

Probability 0.036310000000; percentile 0.882650000000

Applicability

Cited product scope

Trace impact →
CiscoCisco IOS XR Software
[{"status": "affected", "version": "n/a"}]unknown
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_9001:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_9006:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_9010:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_9901:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_9904:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_9906:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_9910:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_9912:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_9922:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:o:cisco:ios_xr:6.4.2:*:*:*:*:*:*:*supported

Assessments

CVSS by origin

8.6
nvd@nist.govCVSS 3.1 · role PrimaryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
7.8
nvd@nist.govCVSS 2.0 · role PrimaryAV:N/AC:L/Au:N/C:N/I:N/A:C
8.6
psirt@cisco.comCVSS 3.1 · role SecondaryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
8.6
ciscoCVSS 3.1 · role unknownCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Limitations and unknowns

  • KEV membership is authoritative for the catalog, not proof of exposure in any environment.
  • EPSS is a dated model probability and not an individual-environment prediction.
  • Affected or fixed status applies only to the exact cited product and version scope; unresolved scope remains unknown.
  • NVD-carried upstream facts remain derivative and are not independent corroboration.
  • Only NVD metrics validated under the generation-bound calculator are Public Priority eligible; direct CVE record metrics remain display-only.
  • NVD CVSS source eligibility is closed: NVD-authored, exact record-source, or registered same-CVE container origin; unmapped sources remain display-only.
  • Factor D is unknown in Public Core because no accepted canonical mapping-obligation ledger is present.
  • Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.