CVE-2025-30649 – “Juniper Networks Junos OS syslog stream TCP transport Improper Input Validation allows CPU Denial of Service”

An Improper Input Validation vulnerability in the syslog stream TCP transport of Juniper Networks Junos OS on MX240, MX480 and MX960 devices with MX-SPC3 Security Services Card allows an unauthenticated, network-based attacker, to send specific spoofed packets to cause a CPU Denial of Service (DoS) to the MX-SPC3 SPUs.

Continued receipt and processing of these specific packets will sustain the DoS condition.

This issue affects Junos OS: * All versions before 22.2R3-S6,
* from 22.4 before 22.4R3-S4,
* from 23.2 before 23.2R2-S3,
* from 23.4 before 23.4R2-S4,
* from 24.2 before 24.2R1-S2, 24.2R2

An indicator of compromise will indicate the SPC3 SPUs utilization has spiked.

For example: 
   user@device> show services service-sets summary
Service sets CPU
Interface configured Bytes used Session bytes used Policy bytes used utilization
“interface” 1 “bytes” (percent%) “sessions” (“percent”%) “bytes” (“percent”%) 99.97 % OVLD <<<<<< look for high CPU usage