A Use After Free vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Juniper Networks Junos OS Evolved allows an attacker sending a BGP update with a specifically malformed AS PATH to cause rpd to crash, resulting in a Denial of Service (DoS). Continuous receipt of the malformed AS PATH attribute will cause a sustained DoS condition.

On all Junos OS and Junos OS Evolved platforms, the rpd process will crash and restart when a specifically malformed AS PATH is received within a BGP update and traceoptions are enabled.

This issue only affects systems with BGP traceoptions enabled and requires a BGP session to be already established. Systems without BGP traceoptions enabled are not impacted by this issue.

This issue affects:

 Junos OS:

• All versions before 21.2R3-S9, 
• all versions of 21.4,
• from 22.2 before 22.2R3-S6, 
• from 22.4 before 22.4R3-S5, 
• from 23.2 before 23.2R2-S3, 
• from 23.4 before 23.4R2-S4, 
• from 24.2 before 24.2R2; 

Junos OS Evolved: 

• All versions before 22.4R3-S5-EVO, 
• from 23.2-EVO before 23.2R2-S3-EVO, 
• from 23.4-EVO before 23.4R2-S4-EVO, 
• from 24.2-EVO before 24.2R2-EVO.

This is a more complete fix for previously published CVE-2024-39549 (JSA83011 [juniper.net]). 

One of the following traceoptions configurations, either at the top level, under [logical-systems], or [routing-instances], is required to be potentially exposed to this issue:

[protocols bgp traceoptions]
[protocols bgp group <group-name> traceoptions]
[protocols bgp group <group-name> neighbor <address> traceoptions]

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen during production usage.

The following software releases have been updated to resolve this specific issue:
Junos OS 21.2R3-S9, 22.2R3-S6, 22.4R3-S5, 23.2R2-S3, 23.4R2-S4, 24.2R2, 24.4R1, and all subsequent releases.
Junos OS Evolved: 22.4R3-S5-EVO, 23.2R2-S3-EVO, 23.4R2-S4-EVO, 24.2R2-EVO, 24.4R1-EVO, and all subsequent releases.

This issue is being tracked as 1810622 which is visible on the Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

Disable BGP traceoptions if they are not being used for active troubleshooting.

2025-07-09: Initial Publication

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• https://www.cve.org/CVERecord?id=CVE-2025-52946