An Improper Handling of Unexpected Data Type vulnerability in the handling of SIP calls in Juniper Networks Junos OS on SRX Series and MX Series platforms allows an attacker to cause a memory leak leading to Denial of Services (DoS). This issue occurs on all MX Series platforms with MS-MPC or MS-MIC card and all SRX Series platforms where SIP ALG is enabled. Successful exploitation of this vulnerability prevents additional SIP calls and applications from succeeding. The SIP ALG needs to be enabled, either implicitly / by default or by way of configuration. To confirm whether SIP ALG is enabled on SRX use the following command: user@host> show security alg status | match sip SIP : Enabled This issue affects Juniper Networks Junos OS on SRX Series and on MX Series: All versions prior to 19.3R3-S7; 19.4 versions prior to 19.4R2-S8, 19.4R3-S10; 20.1 versions 20.1R1 and later versions; 20.2 versions prior to 20.2R3-S6; 20.3 versions prior to 20.3R3-S6; 20.4 versions prior to 20.4R3-S5; 21.1 versions prior to 21.1R3-S5; 21.2 versions prior to 21.2R3-S1; 21.3 versions prior to 21.3R3; 21.4 versions prior to 21.4R2-S2, 21.4R3; 22.1 versions prior to 22.1R1-S2, 22.1R2, 22.1R3-S1. This issue does not affect Juniper Networks Junos OS on SRX Series and on MX Series: All versions prior to 18.2R1.