CVE-2020-1639Network attack vector

CFM daemon crash via malformed Ethernet OAM packet

Published Apr 8, 2020 · Updated Sep 16, 2024

Denial of service in affected Juniper Networks Junos OS releases allows remote attackers to crash CFM with a crafted Ethernet OAM packet. The CFM daemon fails to sanitize malformed Ethernet OAM data before processing it, producing an overflow condition that cores the process. Network access capable of delivering Ethernet OAM traffic is sufficient; continued packet receipt prolongs the service interruption.

CVSS severity7.5
High
EPSS probability1.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in affected Juniper Networks Junos OS releases allows remote attackers to crash CFM with a crafted Ethernet OAM packet. The CFM daemon fails to sanitize malformed Ethernet OAM data before processing it, producing an overflow condition that cores the process. Network access capable of delivering Ethernet OAM traffic is sufficient; continued packet receipt prolongs the service interruption.

The record

CVE
CVE-2020-1639
Published
Apr 8, 2020
Updated
Sep 16, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-703, CWE-755, T1498
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 8, 2020CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=12.3 <12.3R12-S15
  2. Affected versionversion=12.3X48 <12.3X48-D95
  3. Affected versionversion=14.1X50 <14.1X50-D145
  4. Affected versionversion=14.1X53 <14.1X53-D47
  5. Affected versionversion=15.1 <15.1R2
  6. Affected versionversion=15.1X49 <15.1X49-D170
  7. Affected versionversion=15.1X53 <15.1X53-D67

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=12.3 <12.3R12-S15; version=12.3X48 <12.3X48-D95; version=14.1X50 <14.1X50-D145; version=14.1X53 <14.1X53-D47; version=15.1 <15.1R2; version=15.1X49 <15.1X49-D170; version=15.1X53 <15.1X53-D67

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5Juniper Networks, Inc.CVSS:3.1/AV:N/AC:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-703Improper Check or Handling of Exceptional Conditions
CWE-755Improper Handling of Exceptional Conditions
T1498Network 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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