Junos OS (SRX firewalls)
CVE-2024-21617: BGP flap on NSR-enabled devices causes memory leak
An Incomplete Cleanup vulnerability in Nonstop active routing (NSR) component of Juniper Networks Junos OS allows an adjacent, unauthenticated attacker to cause memory leak leading to 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) 21.2 | 21.2R3-S5 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 21.3 | 21.3R3-S4 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 21.4 | 21.4R3-S4 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 22.1 | 22.1R3-S2 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 | 22.3R2-S1, 22.3R3 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 22.4 | 22.4R1-S2, 22.4R2 or later |
| Junos OS (MX Series, PTX Series, ACX Series, EX Series, QFX Series) 0 | Not affected |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
An Incomplete Cleanup vulnerability in Nonstop active routing (NSR) component of Juniper Networks Junos OS allows an adjacent, unauthenticated attacker to cause memory leak leading to Denial of Service (DoS).
On all Junos OS platforms, when NSR is enabled, a BGP flap will cause memory leak. A manual reboot of the system will restore the services.
Note: NSR is not supported on the SRX Series and is therefore not affected by this vulnerability. The memory usage can be monitored using the below commands.
user@host> show chassis routing-engine no-forwarding user@host> show system memory | no-more This issue affects:
Juniper Networks Junos OS
- 21.2 versions earlier than 21.2R3-S5;
- 21.3 versions earlier than 21.3R3-S4;
- 21.4 versions earlier than 21.4R3-S4;
- 22.1 versions earlier than 22.1R3-S2;
- 22.2 versions earlier than 22.2R3-S2;
- 22.3 versions earlier than 22.3R2-S1, 22.3R3;
- 22.4 versions earlier than 22.4R1-S2, 22.4R2.
This issue does not affect Junos OS versions earlier than 20.4R3-S7.
Am I affected?
To be exposed to this issue non-stop routing (NSR) needs to be configured:
[routing-options nonstop-routing]
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.