CVE-2020-5548Network attack vector

Remote hangs or reboots via packet logging

Published Apr 1, 2020 · Updated Aug 4, 2024

Packet-processing denial of service in affected Yamaha router and firewall firmware allows remote attackers to cause hangs or reboots. When filter logging and NOTICE-level syslog output are enabled, a sustained stream of abnormal packets for an undisclosed protocol corrupts memory during received-packet log processing. The condition is unauthenticated and network-reachable, but default configurations disable NOTICE logging; Yamaha reports no information disclosure.

CVSS severity5.9
Medium
EPSS probability1.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Packet-processing denial of service in affected Yamaha router and firewall firmware allows remote attackers to cause hangs or reboots. When filter logging and NOTICE-level syslog output are enabled, a sustained stream of abnormal packets for an undisclosed protocol corrupts memory during received-packet log processing. The condition is unauthenticated and network-reachable, but default configurations disable NOTICE logging; Yamaha reports no information disclosure.

The record

CVE
CVE-2020-5548
Published
Apr 1, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 1, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.1JPCERT/CCAV:N/AC:M/Au:N/C:N/I:N/A:C
5.9JPCERT/CCCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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