Junos OS (SRX firewalls)
CVE-2024-21596: A specific BGP UPDATE message will cause a crash in the backup Routing Engine in NSR-enabled devices
A Heap-based Buffer Overflow vulnerability in the Routing Protocol Daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network based 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 (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 0 | 20.4R3-S9 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 21.2 | 21.2R3-S7 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 21.3 | 21.3R3-S5 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 21.4 | 21.4R3-S5 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 22.1 | 22.1R3-S4 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 22.2 | 22.2R3-S2 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 22.3 | 22.3R3-S1 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 22.4 | 22.4R2-S2, 22.4R3 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 23.1 | 23.1R2 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 23.2 | 23.2R1-S2, 23.2R2 or later |
| Junos OS Evolved (PTX Series, ACX Series, QFX Series) 0 | 21.3R3-S5-EVO or later |
| Junos OS Evolved (PTX Series, ACX Series, QFX Series) 21.4-EVO | 21.4R3-S5-EVO or later |
| Junos OS Evolved (PTX Series, ACX Series, QFX Series) 22.1-EVO | 22.1R3-S4-EVO or later |
| Junos OS Evolved (PTX Series, ACX Series, QFX Series) 22.2-EVO | 22.2R3-S2-EVO or later |
| Junos OS Evolved (PTX Series, ACX Series, QFX Series) 22.4-EVO | 22.4R2-S2-EVO, 22.4R3-EVO or later |
| Junos OS Evolved (PTX Series, ACX Series, QFX Series) 23.1-EVO | 23.1R2-EVO or later |
| Junos OS Evolved (PTX Series, ACX Series, QFX Series) 23.2-EVO | 23.2R1-S2-EVO, 23.2R2-EVO or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
A Heap-based Buffer Overflow vulnerability in the Routing Protocol Daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network based attacker to cause a Denial of Service (DoS).
If an attacker sends a specific BGP UPDATE message to the device, this will cause a memory overwrite and therefore an RPD crash and restart in the backup Routing Engine (RE). Continued receipt of these packets will cause a sustained Denial of Service (DoS) condition in the backup RE.
The primary RE is not impacted by this issue and there is no impact on traffic.
This issue only affects devices with NSR enabled.
Note: NSR is not supported on the SRX Series and is therefore not affected by this vulnerability. This issue requires an attacker to have an established BGP session to a system affected by the issue. This issue affects both eBGP and iBGP implementations.
This issue affects:
Juniper Networks Junos OS
- All versions earlier than 20.4R3-S9;
- 21.2 versions earlier than 21.2R3-S7;
- 21.3 versions earlier than 21.3R3-S5;
- 21.4 versions earlier than 21.4R3-S5;
- 22.1 versions earlier than 22.1R3-S4;
- 22.2 versions earlier than 22.2R3-S2;
- 22.3 versions earlier than 22.3R3-S1;
- 22.4 versions earlier than 22.4R2-S2, 22.4R3;
- 23.1 versions earlier than 23.1R2;
- 23.2 versions earlier than 23.2R1-S2, 23.2R2.
Juniper Networks Junos OS Evolved
- All versions earlier than 21.3R3-S5-EVO;
- 21.4-EVO versions earlier than 21.4R3-S5-EVO;
- 22.1-EVO versions earlier than 22.1R3-S4-EVO;
- 22.2-EVO versions earlier than 22.2R3-S2-EVO;
- 22.3-EVO versions later than 22.3R1-EVO;
- 22.4-EVO versions earlier than 22.4R2-S2-EVO, 22.4R3-EVO;
- 23.1-EVO versions earlier than 23.1R2-EVO;
- 23.2-EVO versions earlier than 23.2R1-S2-EVO, 23.2R2-EVO.
Am I affected?
The following minimal configuration is required:
[protocols bgp]
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.