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CVE-2020-3566

Cisco — Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability

Cisco · CWE-400 — Uncontrolled resource consumption | CWE-770 · in CISA KEV since 2021-11-03

KEV since 2021 · listed over a yearCISA KEVActively Exploited
75

EVRS 75 of 100 Urgent

Patch This Cycle

Rank 1,157 of 2,960 tracked

Raised to the floor for a confirmed exploited vulnerability.

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Why it scores 75

Evidence available: 6 of 7 signals

Listed in the CISA KEV catalog, and an EPSS probability of 0.037.

  • CISA KEVApplied
  • RansomwareDid not apply
  • Vendor exploitationDid not apply
  • EPSSApplied
  • Microsoft Exploitability IndexNot applicable
  • Pre-patch disclosureNo data
  • KEV recencyDid not apply
  • CVSSApplied

The band answers “how soon”, not “how bad”. No data for: Pre-patch disclosure. Why some signals show no data

Fix

No fixed version identified yet

CISA required action

Affected versions

  • ios xr6.4.2
  • asr 9001
  • asr 9006
  • asr 9010
  • asr 9901
  • asr 9904
  • asr 9906
  • asr 9910

+2 more affected products; see the full list at NVD.

Remediation

Apply updates per vendor instructions.

Evidence

Each value with its source
MeasureValueSource
CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is. 8.6 NVD
FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. 0.037 (89.7th pctl) FIRST EPSS
Actively exploitedWhether a source of record has confirmed attacks using it in the wild. Confirmed CISA KEV
Ransomware campaign useWhether CISA has seen ransomware operators use it. Unknown or none CISA KEV
CISA remediation deadlineThe date US federal agencies must have fixed or mitigated it. 2022-05-03 · KEV since 2021 · listed over a year CISA KEV
Public exploit moduleA module existing is not the same as active exploitation. None known Metasploit
EUVD cross-referenceENISA's record: CVSS 8.6 (v3.1), assigned by cisco. Listed ENISA EUVD

Description

NVD

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.

What CISA says to do