Junos OS (SRX firewalls)
CVE-2024-39539: MX Series: Continuous subscriber logins will lead to a memory leak and eventually an FPC crash
A Missing Release of Memory after Effective Lifetime vulnerability in Juniper Networks Junos OS on MX Series allows an unauthenticated adjacent 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) 0 | 21.2R3-S6 or later |
| Junos OS (MX Series) 21.4 | 21.4R3-S6 or later |
| Junos OS (MX Series) 22.1 | 22.1R3-S5 or later |
| Junos OS (MX Series) 22.2 | 22.2R3-S3 or later |
| Junos OS (MX Series) 22.3 | 22.3R3-S2 or later |
| Junos OS (MX Series) 22.4 | 22.4R3 or later |
| Junos OS (MX Series) 23.2 | 23.2R2 or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
A Missing Release of Memory after Effective Lifetime vulnerability in Juniper Networks Junos OS on MX Series allows an unauthenticated adjacent attacker to cause a Denial-of-Service (DoS).
In a subscriber management scenario continuous subscriber logins will trigger a memory leak and eventually lead to an FPC crash and restart.
This issue affects Junos OS on MX Series:
- All version before 21.2R3-S6,
- 21.4 versions before 21.4R3-S6,
- 22.1 versions before 22.1R3-S5,
- 22.2 versions before 22.2R3-S3,
- 22.3 versions before 22.3R3-S2,
- 22.4 versions before 22.4R3,
- 23.2 versions before 23.2R2.
Am I affected?
To be exposed to this vulnerability subscriber management needs to be enabled via:
[system services subscriber-management enable]
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.