CVE-2026-101951: Junos OS and Junos OS Evolved: A BGP peer causes an rpd crash if a malformed MCAST-TREE NLRI is received and readvertised

Published Oct 14, 2026

Updated

An Improper Validation of Consistency within Input vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows a network-adjacent configured BGP peer to cause a denial of service by sending a specifically malformed BGP MCAST-TREE update and this NLRI is then attempted to be readvertised.

Affected Software

2 affected components

Juniper Networks Junos OS

Juniper Networks Junos OS Evolved

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade Juniper Junos OS Evolved to a version that resolves this vulnerability.
Fixed in 23.2R2-S7.7-EVO
Upgrade
Upgrade Juniper Junos OS Evolved to a version that resolves this vulnerability.
Fixed in 23.4R2-S8.11-EVO
Upgrade
Upgrade Juniper Junos OS Evolved to a version that resolves this vulnerability.
Fixed in 24.2R2-S5.6-EVO
Upgrade
Upgrade Juniper Junos OS Evolved to a version that resolves this vulnerability.
Fixed in 24.4R2-S5-EVO
Upgrade
Upgrade Juniper Junos OS Evolved to a version that resolves this vulnerability.
Fixed in 25.2R2-S2-EVO
Upgrade
Upgrade Juniper Junos OS Evolved to a version that resolves this vulnerability.
Fixed in 25.4R1-S3-EVO
Upgrade
Upgrade Juniper Junos OS Evolved to a version that resolves this vulnerability.
Fixed in 25.4R2-EVO
Upgrade
Upgrade Juniper Junos OS Evolved to a version that resolves this vulnerability.
Fixed in 26.2R1-S2-EVO
Upgrade
Upgrade Juniper Junos OS Evolved to a version that resolves this vulnerability.
Fixed in 26.2R2-EVO
Upgrade
Upgrade Juniper Junos OS Evolved to a version that resolves this vulnerability.
Fixed in 26.4R1-EVO
Upgrade
Upgrade Juniper Junos OS to a version that resolves this vulnerability.
Fixed in 23.2R2-S7.7
Upgrade
Upgrade Juniper Junos OS to a version that resolves this vulnerability.
Fixed in 23.4R2-S8.13
Upgrade
Upgrade Juniper Junos OS to a version that resolves this vulnerability.
Fixed in 24.2R2-S5.5
Upgrade
Upgrade Juniper Junos OS to a version that resolves this vulnerability.
Fixed in 24.4R2-S5
Upgrade
Upgrade Juniper Junos OS to a version that resolves this vulnerability.
Fixed in 25.2R2-S2
Upgrade
Upgrade Juniper Junos OS to a version that resolves this vulnerability.
Fixed in 25.4R1-S3
Upgrade
Upgrade Juniper Junos OS to a version that resolves this vulnerability.
Fixed in 25.4R2
Upgrade
Upgrade Juniper Junos OS to a version that resolves this vulnerability.
Fixed in 26.2R1-S2
Upgrade
Upgrade Juniper Junos OS to a version that resolves this vulnerability.
Fixed in 26.2R2
Upgrade
Upgrade Juniper Junos OS to a version that resolves this vulnerability.
Fixed in 26.4R1

Event History

Oct 14, 2026

CVE Published

via MITRE·04:20 PM

Data Sourced

via MITRE·04:20 PM

RemedyDescriptionSeverityWeakness

Frequently Asked Questions

Who can exploit this issue?

A network-adjacent BGP peer that is configured on the affected device can exploit it. The peer must be able to send a specifically malformed BGP MCAST-TREE update.

What condition triggers the denial of service?

The routing protocol daemon crashes when the malformed MCAST-TREE NLRI is received and the device attempts to readvertise that NLRI. The impact is a denial of service affecting rpd.

Is unauthenticated internet access alone sufficient to exploit this vulnerability?

No. The described attacker must be a configured BGP peer and network-adjacent to the affected device.