Junos OS (SRX firewalls)
CVE-2024-21595: EX4100, EX4400, EX4600, QFX5000 Series: A high rate of specific ICMP traffic will cause the PFE to hang
An Improper Validation of Syntactic Correctness of Input vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS allows a network-based, unauthenticated attacker to cause 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 (EX4100, EX4400, EX4600, QFX5000 Series) 21.4R3 | 21.4R3-S4 or later |
| Junos OS (EX4100, EX4400, EX4600, QFX5000 Series) 22.1R3 | 22.1R3-S3 or later |
| Junos OS (EX4100, EX4400, EX4600, QFX5000 Series) 22.2R2 | 22.2R3-S1 or later |
| Junos OS (EX4100, EX4400, EX4600, QFX5000 Series) 22.3 | 22.3R2-S2, 22.3R3 or later |
| Junos OS (EX4100, EX4400, EX4600, QFX5000 Series) 22.4 | 22.4R2 or later |
| Junos OS (EX4100, EX4400, EX4600, QFX5000 Series) 23.1 | 23.1R2 or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
An Improper Validation of Syntactic Correctness of Input vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS allows a network-based, unauthenticated attacker to cause a Denial of Service (DoS).
If an attacker sends high rate of specific ICMP traffic to a device with VXLAN configured, this causes a deadlock of the PFE and results in the device becoming unresponsive. A manual restart will be required to recover the device.
This issue only affects EX4100, EX4400, EX4600, QFX5000 Series devices.
This issue affects:
Juniper Networks Junos OS
- 21.4R3 versions earlier than 21.4R3-S4;
- 22.1R3 versions earlier than 22.1R3-S3;
- 22.2R2 versions earlier than 22.2R3-S1;
- 22.3 versions earlier than 22.3R2-S2, 22.3R3;
- 22.4 versions earlier than 22.4R2;
- 23.1 versions earlier than 23.1R2.
Am I affected?
To be exposed to this issue the device needs be configured for VXLAN with either of the following statements:
[ vlans <vlan> vxlan ] [ routing-instances <routing-instance> vxlan ]
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.