Junos OS (SRX firewalls)
CVE-2024-39554: BGP multipath incremental calculation is resulting in an rpd crash
A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability the Routing Protocol Daemon (rpd) of Juniper Networks Junos OS and Juniper Networks Junos OS Evolved allows an unauthenticated, network-based attacker to inject incremental routing updates when BGP multipath is enabled, causing rpd to crash and restart, resulting in a Denial of Service (DoS).
Published
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 21.1 | 21.1* or later |
| Junos OS 21.2 | 21.2R3-S7 or later |
| Junos OS 21.4 | 21.4R3-S6 or later |
| Junos OS 22.1 | 22.1R3-S5 or later |
| Junos OS 22.2 | 22.2R3-S3 or later |
| Junos OS 22.3 | 22.3R3-S2 or later |
| Junos OS 22.4 | 22.4R3 or later |
| Junos OS 23.2 | 23.2R2 or later |
| Junos OS 0 | Not affected |
| Junos OS Evolved 21.1-EVO | 21.1*-EVO or later |
| Junos OS Evolved 21.2-EVO | 21.2*-EVO or later |
| Junos OS Evolved 21.4-EVO | 21.4R3-S6-EVO or later |
| Junos OS Evolved 22.1-EVO | 22.1R3-S5-EVO or later |
| Junos OS Evolved 22.2-EVO | 22.2R3-S3-EVO or later |
| Junos OS Evolved 22.3-EVO | 22.3R3-S2-EVO or later |
| Junos OS Evolved 22.4-EVO | 22.4R3-EVO or later |
| Junos OS Evolved 23.2-EVO | 23.2R2-EVO or later |
| Junos OS Evolved 0 | Not affected |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability the
Routing Protocol Daemon (rpd)
of Juniper Networks Junos OS and Juniper Networks Junos OS Evolved allows an unauthenticated, network-based attacker to inject incremental routing updates when BGP multipath is enabled, causing rpd to crash and restart, resulting in a Denial of Service (DoS). Since this is a timing issue (race condition), the successful exploitation of this vulnerability is outside the attacker's control. However, continued receipt and processing of this packet may create a sustained Denial of Service (DoS) condition.
On all Junos OS and Junos OS Evolved platforms with BGP multipath enabled, a specific multipath calculation removes the original next hop from the multipath lead routes nexthop-set. When this change happens, multipath relies on certain internal timing to record the update. Under certain circumstance and with specific timing, this could result in an rpd crash.
This issue only affects systems with BGP multipath enabled.
This issue affects:
Junos OS:
- All versions of 21.1
- from 21.2 before 21.2R3-S7,
- from 21.4 before 21.4R3-S6,
- from 22.1 before 22.1R3-S5,
- from 22.2 before 22.2R3-S3,
- from 22.3 before 22.3R3-S2,
- from 22.4 before 22.4R3,
- from 23.2 before 23.2R2.
Junos OS Evolved:
- All versions of 21.1-EVO,
- All versions of 21.2-EVO,
- from 21.4-EVO before 21.4R3-S6-EVO,
- from 22.1-EVO before 22.1R3-S5-EVO,
- from 22.2-EVO before 22.2R3-S3-EVO,
- from 22.3-EVO before 22.3R3-S2-EVO,
- from 22.4-EVO before 22.4R3-EVO,
- from 23.2-EVO before 23.2R2-EVO.
Versions of Junos OS before 21.1R1 are unaffected by this vulnerability. Versions of Junos OS Evolved before 21.1R1-EVO are unaffected by this vulnerability.
Am I affected?
A sample BGP multipath configuration is shown below:
[ protocols bgp group <name> multipath ]
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 13 Oct 2026.