Junos OS (SRX firewalls)
CVE-2026-102027: A configured BGP neighbor causes rpd crash when multipath next-hops are processed
An Incorrect Calculation of Buffer Size vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows a configured eBGP neighbor to cause an rpd crash via BGP labeled-unicast UPDATEs when the affected multipath features are enabled.
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 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 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 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
A miscalculation of buffer size in the routing protocol daemon allows a configured eBGP neighbor to crash the service by sending specific BGP labeled-unicast UPDATE messages. This attack requires no authentication or user interaction and can be executed remotely over the network when multipath features are enabled.
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 Incorrect Calculation of Buffer Size vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows a configured eBGP neighbor to cause an rpd crash via BGP labeled-unicast UPDATEs when the affected multipath features are enabled.
Am I affected?
[ protocols bgp multipath list-nexthop ] [ routing-options forwarding-table chained-composite-next-hop ingress labeled-bgp inet ]
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.