CVE-2020-1638Network attack vector

FPC restart via specific IPv4 packet

Published Apr 8, 2020 · Updated Sep 17, 2024

Denial of service in Junos OS and Junos OS Evolved allows remote attackers to restart an FPC by sending a specific IPv4 packet to the device. The affected FPC packet-processing path restarts when it processes the packet; Juniper identifies CWE-467 but does not disclose the packet fields or code locus. The packet must reach the Routing Engine through edge and control-plane filters on specified MX, PTX, or QFX hardware, and repeated packets drop all traffic through the FPC.

CVSS severity7.5
High
EPSS probability1.32%
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 Junos OS and Junos OS Evolved allows remote attackers to restart an FPC by sending a specific IPv4 packet to the device. The affected FPC packet-processing path restarts when it processes the packet; Juniper identifies CWE-467 but does not disclose the packet fields or code locus. The packet must reach the Routing Engine through edge and control-plane filters on specified MX, PTX, or QFX hardware, and repeated packets drop all traffic through the FPC.

The record

CVE
CVE-2020-1638
Published
Apr 8, 2020
Updated
Sep 17, 2024
Vendor
Juniper Networks
Product
Junos OS Evolved
Classifications
CWE-467, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 8, 2020CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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?

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

  1. Affected versionversion=19.2-EVO
  2. Affected versionversion=19.3-EVO 19.2-EVO
  3. Affected versionversion=19.4-EVO <19.4R2-EVO

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OS Evolvedversion=19.2-EVO; version=19.3-EVO 19.2-EVO; version=19.4-EVO <19.4R2-EVO
Juniper Networks · Junos OSversion=19.2 <19.2R1-S4, 19.2R2; version=19.3 <19.3R2-S2, 19.3R3; version=19.4 <19.4R1-S1, 19.4R2

Published CVSS scores

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

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-467Use of sizeof() on a Pointer Type
T1499.004Application or System Exploitation

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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