Junos OS (SRX firewalls)
CVE-2024-30378: MX Series: bbe-smgd process crash upon execution of specific CLI commands
A Use After Free vulnerability in command processing of Juniper Networks Junos OS on MX Series allows a local, authenticated attacker to cause the broadband edge service manager daemon (bbe-smgd) to crash upon execution of specific CLI commands, creating a Denial of Service (DoS) condition.
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) 0 | 20.4R3-S5 or later |
| Junos OS (MX Series) 21.1 | 21.1R3-S4 or later |
| Junos OS (MX Series) 21.2 | 21.2R3-S3 or later |
| Junos OS (MX Series) 21.3 | 21.3R3-S5 or later |
| Junos OS (MX Series) 21.4 | 21.4R3-S5 or later |
| Junos OS (MX Series) 22.1 | 22.1R3 or later |
| Junos OS (MX Series) 22.2 | 22.2R3 or later |
| Junos OS (MX Series) 22.3 | 22.3R2 or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
A Use After Free vulnerability in command processing of Juniper Networks Junos OS on MX Series allows a local, authenticated attacker to cause the broadband edge service manager daemon (bbe-smgd) to crash upon execution of specific CLI commands, creating a Denial of Service (DoS) condition. The process crashes and restarts automatically.
When specific CLI commands are executed, the bbe-smgd daemon attempts to write into an area of memory (mgd socket) that was already closed, causing the process to crash. This process manages and controls the configuration of broadband subscriber sessions and services. While the process is unavailable, additional subscribers will not be able to connect to the device, causing a temporary Denial of Service condition.
This issue only occurs if Graceful Routing Engine Switchover (GRES) and Subscriber Management are enabled. This issue affects Junos OS:
- All versions before 20.4R3-S5,
- from 21.1 before 21.1R3-S4,
- from 21.2 before 21.2R3-S3,
- from 21.3 before 21.3R3-S5,
- from 21.4 before 21.4R3-S5,
- from 22.1 before 22.1R3,
- from 22.2 before 22.2R3,
- from 22.3 before 22.3R2;
Am I affected?
Subscriber Services (Broadband Edge) and GRES must be enabled to be vulnerable to this issue:
[edit system services] subscriber-management enable;
[edit chassis redundancy] graceful-switchover;
Workarounds
Use access lists or firewall filters to limit access to the CLI only from trusted hosts and administrators.
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.