SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-31375

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…

MEDIUM 5.3EPSS 0.80%

Does this matter?

Lower severity and a low EPSS score (0.80%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 3.1
5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS
0.80% probability · 56th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-20, CWE-358
Affected
juniper/junos
Source
sirt@juniper.net
EPSS trend
0%3%5%26 October 2026: 0.80%26 October 202626 October 2026

EPSS 0.8% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.