Junos OS (SRX firewalls)
CVE-2026-101951: A BGP peer causes an rpd crash if a malformed MCAST-TREE NLRI is received and readvertised
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.
Published Juniper Networks advisory JSA112187
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Junos OS 0 | 23.2R2-S7.7 or later |
| Junos OS 23.4 | 23.4R2-S8.13 or later |
| Junos OS 24.2 | 24.2R2-S5.5 or later |
| Junos OS 24.4 | 24.4R2-S5 or later |
| Junos OS 25.2 | 25.2R2-S2 or later |
| Junos OS 25.4 | 25.4R1-S3 or later |
| Junos OS 26.2 | 26.2R1-S2 or later |
| Junos OS Evolved 0 | 23.2R2-S7.7-EVO or later |
| Junos OS Evolved 23.4 | 23.4R2-S8.11-EVO or later |
| Junos OS Evolved 24.2 | 24.2R2-S5.6-EVO or later |
| Junos OS Evolved 24.4 | 24.4R2-S5-EVO or later |
| Junos OS Evolved 25.2 | 25.2R2-S2-EVO or later |
| Junos OS Evolved 25.4 | 25.4R1-S3-EVO or later |
| Junos OS Evolved 26.2 | 26.2R1-S2-EVO or later |
| Junos OS Evolved 23.4X100 | See the advisory |
| Junos OS Evolved 25.2X100 | 25.2X100-D35-EVO or later |
| Junos OS Evolved 25.4X300 | 25.4X300-D40-EVO or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
In short
An improper input validation vulnerability in the routing protocol daemon of Juniper Networks Junos OS and Junos OS Evolved allows a network-adjacent configured BGP peer to cause a denial of service. The attacker achieves this by sending a specifically malformed BGP MCAST-TREE update that triggers an error when readvertised. This attack requires network-adjacent access without requiring authentication or user interaction.
Written by a language model from the vendor's description. Versions, fixes and exploitation status on this page come straight from the vendor and CISA.
The vendor's description
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.
Am I affected?
[ protocols bgp group family inet-/inet6-bgpmcast signaling ]
Workarounds
There are no known workarounds for this issue.
Exploitation
Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 19 Oct 2026.