An Expected Behavior Violation vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated adjacent attacker sending a valid BGP UPDATE packet to cause a BGP session reset, resulting in a Denial of Service (DoS). 

Continuous receipt and processing of this packet will create a sustained Denial of Service (DoS) condition.

This issue affects iBGP and eBGP and both IPv4 and IPv6 are affected by this vulnerability.

This issue affects Junos OS:

• All versions before 21.2R3-S9,
• from 21.4 before 21.4R3-S11,
• from 22.2 before 22.2R3-S7,
• from 22.4 before 22.4R3-S7,
• from 23.2 before 23.2R2-S4,
• from 23.4 before 23.4R2-S4,
• from 24.2 before 24.2R2,
• from 24.4 before 24.4R1-S3, 24.4R2

Junos OS Evolved:

• All versions before 22.2R3-S7-EVO,
• from 22.4-EVO before 22.4R3-S7-EVO,
• from 23.2-EVO before 23.2R2-S4-EVO,
• from 23.4-EVO before 23.4R2-S4-EVO,
• from 24.2-EVO before 24.2R2-EVO,
• from 24.4-EVO before 24.4R1-S3-EVO, 24.4R2-EVO.

One of the following minimal configurations is necessary to be exposed to this issue:
  [protocols bgp group <group-name> neighbor <peer-ip-address> family inet6-vpn unicast]
or
  [protocols bgp group <group-name> family inet6-vpn unicast]
or
  [protocols bgp family inet6-vpn unicast]

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, 21.4R3-S11, 22.2R3-S7, 22.4R3-S7, 23.2R2-S4, 23.4R2-S4, 24.2R2, 24.4R1-S3, 24.4R2, 25.2R1, and all subsequent releases.
Junos OS Evolved: 22.2R3-S7-EVO, 22.4R3-S7-EVO, 23.2R2-S4-EVO, 23.4R2-S4-EVO, 24.2R2-EVO, 24.4R1-S3-EVO, 24.4R2-EVO, 25.2R1-EVO, and all subsequent releases.

This issue is being tracked as 1855477 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).

There are no known workarounds for this issue.

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-2025-52953