Junos OS (SRX firewalls)
CVE-2025-52960: SRX Series and MX Series: Receipt of specific SIP packets in a high utilization situation causes a flowd/mspmand crash
A Buffer Copy without Checking Size of Input vulnerability in the Session Initialization Protocol (SIP) ALG of Juniper Networks Junos OS on MX Series and SRX Series 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 (SRX Series, MX Series) 0 | 22.4R3-S7 or later |
| Junos OS (SRX Series, MX Series) 23.2 | 23.2R2-S4 or later |
| Junos OS (SRX Series, MX Series) 23.4 | 23.4R2-S5 or later |
| Junos OS (SRX Series, MX Series) 24.2 | 24.2R2 or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
A Buffer Copy without Checking Size of Input vulnerability in the
Session Initialization Protocol (SIP) ALG of Juniper Networks Junos OS on MX Series and SRX Series allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS).
When memory utilization is high, and specific SIP packets are received, flowd/mspmand crashes. While the system recovers automatically, the disruption can significantly impact service stability. Continuous receipt of these specific SIP packets, while high utilization is present, will cause a sustained DoS condition. The utilization is outside the attackers control, so they would not be able to deterministically exploit this. This issue affects Junos OS on SRX Series and MX Series:
- All versions before 22.4R3-S7,
- from 23.2 before 23.2R2-S4,
- from 23.4 before 23.4R2-S5,
- from 24.2 before 24.2R2.
Am I affected?
To be affected the SIP ALG needs to be enabled, either implicitly / by default or by way of configuration.
Please verify on SRX, and MX with SPC3 with:
user@host> show security alg status | match sip SIP : Enabled
Please verify on MX whether the following is configured:
[services ... rule <rule-name> (term <term-name> ) from/match application/application-set <name>]where either
a. name = junos-sipor an application or application-set refers to SIP:
b. [applications application <name> application-protocol sip]or
c. [applications application-set <name> application junos-sip]
Workarounds
There are no known workarounds for this issue.
To reduce the risk of exploitation customers not requiring the SIP ALG functionality could explicitly disable it (in case it's by default enabled) by configuring:
[ security alg sip disable ]
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.