Junos OS: Receipt of a specific BGP update may cause RPKI policy-checks to be bypassed

published 2021-10-19 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-18285

cvss: 7.2; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.8%; EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits: 0; none known

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.

Patch / fix

fixed in 1

Juniper Networks Junos OS 12.3R12-S18, 15.1R7-S9, 17.2R3-S3, 17.3R3-S7, 17.4R2-S9, 17.4R3, 18.1R3-S13, 18.2R3-S3, 18.3R3-S1, 18.4R3, 19.1R2, 19.2R2, 19.3R2

Exploit prediction

0.80% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.2	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L
NVD	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:P/A:N

Affected products

Juniper Networks Junos OS

Classification

Weakness

CWE-358 Improperly Implemented Security Check for Standard
CWE-20 Improper Input Validation

References

kb.juniper.net /JSA11240
vendor-advisory

Sources

CVE List CVE-2021-31375
NVD CVE-2021-31375

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Summary