CVE detail

CVE-2021-0236 — CVE-2021-0236

Published 2021-04-22 · Modified 2026-06-17 · Vendor juniper · Product junos · Source nvd
MEDIUM
severity
CVSS-derived band
6.5
CVSS v3
0–10 scale
0.0085
EPSS probability
exploitation probability, 30d
55.0%
EPSS percentile
percentile vs all CVEs
NOT LISTED
CISA KEV
known exploited catalog

Description

Due to an improper check for unusual or exceptional conditions in Juniper Networks Junos OS and Junos OS Evolved the Routing Protocol Daemon (RPD) service, upon receipt of a specific matching BGP packet meeting a specific term in the flowspec configuration, crashes and restarts causing a Denial of Service (DoS). Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue affects only Multiprotocol BGP (MP-BGP) VPNv6 FlowSpec deployments. This issue affects: Juniper Networks Junos OS: 18.4 versions prior to 18.4R1-S8, 18.4R2-S7, 18.4R3-S7; 19.1 versions prior to 19.1R2-S2, 19.1R3-S4; 19.2 versions prior to 19.2R1-S6, 19.2R3-S2; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R2-S4, 19.4R3-S1; 20.1 versions prior to 20.1R

Remediation

vendor remediation guidance

The following software releases have been updated to resolve this specific issue: Junos OS: 18.4R1-S8, 18.4R2-S7, 18.4R3-S7, 19.1R2-S2, 19.1R3-S4, 19.2R1-S6, 19.2R3-S2, 19.3R3-S2, 19.4R2-S4, 19.4R3-S1, 20.1R2, 20.1R3, 20.2R2, 20.2R3, 20.3R1-S1, 20.3R2, 20.4R1 and all subsequent releases. Junos OS Evolved: 20.3R2-EVO, 20.4R1-EVO, and all subsequent releases.

workarounds

Do not configure "family inet6-vpn flow" under BGP if no inet6-vpn routes are required to be received.

ProductVulnerable rangeFixed versionAdvisory
Juniper Networks Junos OS>=18.4<18.4R1-S8, 18.4R2-S7, 18.4R3-S718.4R1-S8, 18.4R2-S7, 18.4R3-S7advisory ↗
Juniper Networks Junos OS>=19.1<19.1R2-S2, 19.1R3-S419.1R2-S2, 19.1R3-S4advisory ↗
Juniper Networks Junos OS>=19.2<19.2R1-S6, 19.2R3-S219.2R1-S6, 19.2R3-S2advisory ↗
Juniper Networks Junos OS>=19.3<19.3R3-S219.3R3-S2advisory ↗
Juniper Networks Junos OS>=19.4<19.4R2-S4, 19.4R3-S119.4R2-S4, 19.4R3-S1advisory ↗
Juniper Networks Junos OS>=20.1<20.1R2, 20.1R3, 20.1R3-EVO20.1R2, 20.1R3, 20.1R3-EVOadvisory ↗
Juniper Networks Junos OS>=20.2<20.2R2, 20.2R3, 20.2R3-EVO20.2R2, 20.2R3, 20.2R3-EVOadvisory ↗
Juniper Networks Junos OS>=20.3<20.3R1-S1, 20.3R2, 20.3R2-EVO20.3R1-S1, 20.3R2, 20.3R2-EVOadvisory ↗
Juniper Networks Junos OS Evolved>=20.3-EVO<20.3R2-EVO20.3R2-EVOadvisory ↗

References

cvedb.io · NVD · CISA KEV · FIRST EPSS · vendor advisories (CVE Program List v5). Informational only, no warranty — verify every remediation against the vendor advisory before acting on it. This product uses data from the NVD API but is not endorsed or certified by the NVD, CISA, FIRST.org or any vendor named. CVE® is a registered trademark of The MITRE Corporation.