An Improper Validation of Specified Quantity in Input vulnerability in the TCP proxy plugin of Juniper Networks Junos OS on MX Series with SPC3, and SRX Series allows an unauthenticated, network-based attacker to cause a complete Denial of Service (DoS).

When TCP proxy is engaged in a flow session, to support ALGs, Advanced Anti-Malware, ICAP or UTM, a TCP packet with specifically malformed TCP header will cause flow processing daemon (flowd) to crash and restart. This causes a complete service outage until the system has automatically recovered.

This issue affects Junos OS on MX with SPC3, and SRX Series:

23.4 versions before 23.4R2-S7,  24.2 versions before 24.2R2-S4,  24.4 versions before 24.4R2-S3, 25.2 versions before 25.2R2.

This issue does not affect releases before 23.4R1.