CVE-2025-52946: With traceoptions enabled, receipt of malformed AS PATH causes RPD crash

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	21.2R3-S9 or later
Junos OS 21.4	* or later
Junos OS 22.2	22.2R3-S6 or later
Junos OS 22.4	22.4R3-S5 or later
Junos OS 23.2	23.2R2-S3 or later
Junos OS 23.4	23.4R2-S4 or later
Junos OS 24.2	24.2R2 or later
Junos OS Evolved 0	22.4R3-S5-EVO or later
Junos OS Evolved 23.2-EVO	23.2R2-S3-EVO or later
Junos OS Evolved 23.4-EVO	23.4R2-S4-EVO or later
Junos OS Evolved 24.2-EVO	24.2R2-EVO or later

Always confirm against the vendor advisory, which lists every fixed hotfix.

What it is

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).

Am I affected?

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]

Workarounds

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

Exploitation

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

KEV status, EPSS score and vendor data refreshed automatically, last on 13 Oct 2026.