Junos OS (SRX firewalls)
CVE-2024-39547: cRPD: Receipt of crafted TCP traffic can trigger high CPU utilization
An Improper Handling of Exceptional Conditions vulnerability in the rpd-server of Juniper Networks Junos OS and Junos OS Evolved within cRPD allows an unauthenticated network-based attacker sending crafted TCP traffic to the routing engine (RE) to cause a CPU-based 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 (cRPD) 0 | 21.2R3-S8 or later |
| Junos OS (cRPD) 21.4 | 21.4R3-S7 or later |
| Junos OS (cRPD) 22.1 | 22.1R3-S6 or later |
| Junos OS (cRPD) 22.2 | 22.2R3-S4 or later |
| Junos OS (cRPD) 22.3 | 22.3R3-S3 or later |
| Junos OS (cRPD) 22.4 | 22.4R3-S2 or later |
| Junos OS (cRPD) 23.2 | 23.2R2-S2 or later |
| Junos OS (cRPD) 24.2 | 24.2R2 or later |
| Junos OS Evolved (cRPD) 0 | 21.4R3-S7-EVO or later |
| Junos OS Evolved (cRPD) 22.2-EVO | 22.2R3-S4-EVO or later |
| Junos OS Evolved (cRPD) 22.3-EVO | 22.3R3-S3-EVO or later |
| Junos OS Evolved (cRPD) 22.4-EVO | 22.4R3-S2-EVO or later |
| Junos OS Evolved (cRPD) 23.2-EVO | 23.2R2-EVO or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
An Improper Handling of Exceptional Conditions vulnerability in the rpd-server of Juniper Networks Junos OS and Junos OS Evolved within cRPD allows an unauthenticated network-based attacker sending crafted TCP traffic to the routing engine (RE) to cause a CPU-based Denial of Service (DoS).
If specially crafted TCP traffic is received by the control plane, or a TCP session terminates unexpectedly, it will cause increased control plane CPU utilization by the rpd-server process.
While not explicitly required, the impact is more severe when RIB sharding is enabled.
Task accounting shows unexpected reads by the RPD Server jobs for shards:
user@junos> show task accounting detail ... read:RPD Server.0.0.0.0+780.192.168.0.78+48886 TOT:00000003.00379787 MAX:00000000.00080516 RUNS: 233888\ read:RPD Server.0.0.0.0+780.192.168.0.78+49144 TOT:00000004.00007565 MAX:00000000.00080360 RUNS: 233888\ read:RPD Server.0.0.0.0+780.192.168.0.78+49694 TOT:00000003.00600584 MAX:00000000.00080463 RUNS: 233888\ read:RPD Server.0.0.0.0+780.192.168.0.78+50246 TOT:00000004.00346998 MAX:00000000.00080338 RUNS: 233888\
This issue affects:
Junos OS with cRPD:
- All versions before 21.2R3-S8,
- 21.4 before 21.4R3-S7,
- 22.1 before 22.1R3-S6,
- 22.2 before 22.2R3-S4,
- 22.3 before 22.3R3-S3,
- 22.4 before 22.4R3-S2,
- 23.2 before 23.2R2-S2,
- 24.2 before 24.2R2;
Junos OS Evolved with cRPD:
- All versions before 21.4R3-S7-EVO,
- 22.2 before 22.2R3-S4-EVO,
- 22.3 before 22.3R3-S3-EVO,
- 22.4 before 22.4R3-S2-EVO,
- 23.2 before 23.2R2-EVO.
Am I affected?
rpd-server is enabled by default in cRPD. No specific configuration is required to be vulnerable to this issue.
BGP RIB sharding is enabled using the following configuration:
[set system processes routing bgp rib-sharding]
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.