CVE-2021-31375

Name: CVE-2021-31375
Creator: NVD / NIST
Published: 2021-10-19T19:15:10.707+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 0.78%

Last modified Jun 17, 2026

CVE-2021-31375 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. An Improper Input Validation vulnerability in routing process daemon (RPD) of Juniper Networks Junos OS devices configured with BGP origin validation using Resource Public Key Infrastructure (RPKI), allows an attacker to send a specific BGP update which may cause RPKI policy-checks to be bypassed. This, in turn, may allow a spoofed advertisement to be accepted or propagated. EPSS estimates a 0.78% chance of exploitation in the next 30 days.

Description

An Improper Input Validation vulnerability in routing process daemon (RPD) of Juniper Networks Junos OS devices configured with BGP origin validation using Resource Public Key Infrastructure (RPKI), allows an attacker to send a specific BGP update which may cause RPKI policy-checks to be bypassed. This, in turn, may allow a spoofed advertisement to be accepted or propagated. This issue affects: Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S18; 15.1 versions prior to 15.1R7-S9; 17.2 versions prior to 17.2R3-S3; 17.3 versions prior to 17.3R3-S7; 17.4 versions prior to 17.4R2-S9, 17.4R3; 18.1 versions prior to 18.1R3-S13; 18.2 versions prior to 18.2R3-S3; 18.3 versions prior to 18.3R3-S1; 18.4 versions prior to 18.4R3; 19.1 versions prior to 19.1R2; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R2.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS Probability

0.78%

51.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Juniper	Junos	12.3
Juniper	Junos	15.1
Juniper	Junos	17.2
Juniper	Junos	17.3
Juniper	Junos	17.4
Juniper	Junos	18.1
Juniper	Junos	18.2
Juniper	Junos	18.3
Juniper	Junos	18.4
Juniper	Junos	19.1
Juniper	Junos	19.2
Juniper	Junos	19.3

References

https://kb.juniper.net/JSA11240Vendor Advisory
https://kb.juniper.net/JSA11240Vendor Advisory

Timeline

Published: Oct 19, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-31375?

How severe is CVE-2021-31375?

CVE-2021-31375 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.78% probability of exploitation in the next 30 days.

How do I fix CVE-2021-31375?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-31375?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST