Junos OS syslog TCP DoS via invalid packets on MX-SPC3 (pre-22.2R3, pre-23.4R2)
CVE-2025-30649 Published on April 9, 2025
Junos OS: MX240, MX480, MX960 with SPC3: An attacker sending specific packets will cause a CPU utilization DoS.
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
Vulnerability Analysis
CVE-2025-30649 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Timeline
Initial Publication
Weakness Type
Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
Products Associated with CVE-2025-30649
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Affected Versions
Juniper Networks Junos OS:- Before 22.2R3-S6 is affected.
- Version 22.4 and below 22.4R3-S4 is affected.
- Version 23.2 and below 23.2R2-S3 is affected.
- Version 23.4 and below 23.4R2-S4 is affected.
- Version 24.2 and below 24.2R1-S2, 24.2R2 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.