CVE-2021-31374

mediumpriority · track · 20EPSS 0.010 · 63 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.02% (63rd) EPSS

CVSS 5 · medium

Is it mine?

28 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · nvd

EPSS · scored 2026-10-27

On Juniper Networks Junos OS and Junos OS Evolved devices processing a specially crafted BGP UPDATE or KEEPALIVE message can lead to a routing process daemon (RPD) crash and restart, causing a Denial of Service (DoS). Continued receipt and processing of this message will create a sustained Denial of Service (DoS) condition. This issue affects both IBGP and EBGP deployments over IPv4 or IPv6. This issue affects: Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R2-S13, 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R2-S8, 18.2R3-S7; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S7, 18.4R3-S7; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S4; 19.2 versions prior to 19.2R1-S6, 19.2R3-S1; 19.3 versions prior to 19.3R2-S5, 19.3R3-S1; 19.4 versions prior to 19.4R1-S4, 19.4R1-S4, 19.4R2-S3, 19.4R3-S1; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R2; 20.3 versions prior to 20.3R1-S1, 20.3R2. Juniper Networks Junos OS Evolved: 20.3 versions prior to 20.3R2-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: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-787US

affected products (28)

Products and version ranges known to be affected.

Juniper Networks Junos OS17.3 → 17.3R3-S11enisa_euvdEU
Juniper Networks Junos OS17.4 → 17.4R2-S13, 17.4R3-S4enisa_euvdEU
Juniper Networks Junos OS18.1 → 18.1R3-S12enisa_euvdEU
Juniper Networks Junos OS18.2 → 18.2R2-S8, 18.2R3-S7enisa_euvdEU
Juniper Networks Junos OS18.3 → 18.3R3-S4enisa_euvdEU
Juniper Networks Junos OS18.4 → 18.4R1-S8, 18.4R2-S7, 18.4R3-S7enisa_euvdEU
Juniper Networks Junos OS19.1 → 19.1R1-S6, 19.1R2-S2, 19.1R3-S4enisa_euvdEU
Juniper Networks Junos OS19.2 → 19.2R1-S6, 19.2R3-S1enisa_euvdEU
Juniper Networks Junos OS19.3 → 19.3R2-S5, 19.3R3-S1enisa_euvdEU
Juniper Networks Junos OS19.4 → 19.4R1-S4, 19.4R2-S3, 19.4R3-S1enisa_euvdEU
Juniper Networks Junos OS20.1 → 20.1R2enisa_euvdEU
Juniper Networks Junos OS20.2 → 20.2R2enisa_euvdEU
Juniper Networks Junos OS20.3 → 20.3R1-S1, 20.3R2enisa_euvdEU
Juniper Networks Junos OS Evolved20.3 → 20.3R2-EVOenisa_euvdEU
juniper junos= 17.3nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos= 17.4nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos= 18.1nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos= 18.2nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos= 18.3nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos= 18.4nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*

showing 20 of 28

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd NVD CVE.org MITRE

published 2021-10-19modified 2026-06-17

references (6)

External citations — patches, advisories, analysis.

scry

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