An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS).

If specific traffic is received on MX Series and its rate exceeds the respective DDoS protection limit the ingress PFE will crash and restart. Continued receipt of this traffic will create a sustained DoS condition.
 

This issue affects Juniper Networks Junos OS on MX Series:

All versions prior to 19.1R3-S10;

19.2 versions prior to 19.2R3-S7;

19.3 versions prior to 19.3R3-S8;

19.4 versions prior to 19.4R3-S11;

20.2 versions prior to 20.2R3-S5;

20.4 versions prior to 20.4R3-S6;

21.1 versions prior to 21.1R3-S5;

21.2 versions prior to 21.2R3-S4;

21.3 versions prior to 21.3R3;

21.4 versions prior to 21.4R3;

22.1 versions prior to 22.1R2.

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen during production usage.

This issue has been assigned CVE-2023-28976.

The following software releases have been updated to resolve this specific issue: 19.4R3-S11, 20.2R3-S5, 20.4R3-S6, 21.1R3-S5, 21.2R3-S4, 21.3R3, 21.4R3, 22.1R2, 22.2R1, and all subsequent releases.

This issue is being tracked as 1647532

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

• 2023-04-12: Initial Publication.

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2023-28976 at cve.mitre.org