CVE-2020-1638

mediumpriority · track · 30EPSS 0.013 · 71 %ileEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.32% (71st) EPSS

CVSS 5 · medium

Is it mine?

21 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

EPSS · scored 2026-10-27

The FPC (Flexible PIC Concentrator) of Juniper Networks Junos OS and Junos OS Evolved may restart after processing a specific IPv4 packet. Only packets destined to the device itself, successfully reaching the RE through existing edge and control plane filtering, will be able to cause the FPC restart. When this issue occurs, all traffic via the FPC will be dropped. By continuously sending this specific IPv4 packet, an attacker can repeatedly crash the FPC, causing an extended Denial of Service (DoS) condition. This issue can only occur when processing a specific IPv4 packet. IPv6 packets cannot trigger this issue. This issue affects: Juniper Networks Junos OS on MX Series with MPC10E or MPC11E and PTX10001: 19.2 versions prior to 19.2R1-S4, 19.2R2; 19.3 versions prior to 19.3R2-S2, 19.3R3; 19.4 versions prior to 19.4R1-S1, 19.4R2. Juniper Networks Junos OS Evolved on on QFX5220, and PTX10003 series: 19.2-EVO versions; 19.3-EVO versions; 19.4-EVO versions prior to 19.4R2-EVO. This issue does not affect Junos OS versions prior to 19.2R1. This issue does not affect Junos OS Evolved versions prior to 19.2R1-EVO.

cvss

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–7.5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.17.5highAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · sirt@juniper.net USexploitability 3.9 · impact 3.6

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-20USCWE-467USCWE-467US

affected products (21)

Products and version ranges known to be affected.

Juniper Networks Junos OS19.2 → 19.2R1-S4, 19.2R2enisa_euvdEU
Juniper Networks Junos OS19.3 → 19.3R2-S2, 19.3R3enisa_euvdEU
Juniper Networks Junos OS19.4 → 19.4R1-S1, 19.4R2enisa_euvdEU
Juniper Networks Junos OS Evolved≤ 19.3-EVO 19.2-EVOenisa_euvdEU
Juniper Networks Junos OS Evolved≤ 19.2-EVOenisa_euvdEU
Juniper Networks Junos OS Evolved19.4-EVO → 19.4R2-EVOenisa_euvdEU
Juniper Networks Inc. JunOS≤ 19.4R1-S1fstec_bduRU
Juniper Networks Inc. JunOS≤ 19.4R2fstec_bduRU
Juniper Networks Inc. JunOS≤ 19.3R3fstec_bduRU
Juniper Networks Inc. JunOS≤ 19.3R2-S2fstec_bduRU
Juniper Networks Inc. JunOS≤ 19.2R2fstec_bduRU
Juniper Networks Inc. JunOS≤ 19.2R1-S4fstec_bduRU
Juniper Networks Inc. Junos OS Evolved≤ 19.4R2-EVOfstec_bduRU
Juniper Networks Inc. Junos OS Evolved≤ 19.2-EVOfstec_bduRU
Juniper Networks Inc. Junos OS Evolved≤ 19.3-EVOfstec_bduRU
juniper junos= 19.2nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos= 19.3nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos= 19.4nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos os evolved= 19.2nvdUScpe:2.3:o:juniper:junos_os_evolved:*:*:*:*:*:*:*:*
juniper junos os evolved= 19.3nvdUScpe:2.3:o:juniper:junos_os_evolved:*:*:*:*:*:*:*:*

showing 20 of 21

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu nvd NVD CVE.org MITRE

published 2020-04-08modified 2026-06-17

references (6)

External citations — patches, advisories, analysis.

scry

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