An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX Series allows a network-based, unauthenticated attacker to cause a Denial of Service (DoS).

On Junos MX Series platforms with Precision Time Protocol (PTP) configured, a prolonged routing protocol churn can lead to an FPC crash and restart.

This issue affects Juniper Networks Junos OS on MX Series:

• All versions prior to 20.4R3-S4;
• 21.1 version 21.1R1 and later versions;
• 21.2 versions prior to 21.2R3-S2;
• 21.3 versions prior to 21.3R3-S5;
• 21.4 versions prior to 21.4R3;
• 22.1 versions prior to 22.1R3;
• 22.2 versions prior to 22.2R1-S1, 22.2R2.

To be exposed to this issue an FPC must have at least one interface with PTP configured like in the following example:

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-2023-44199.

The following software releases have been updated to resolve this specific issue: 20.4R3-S4, 21.2R3-S2, 21.3R3-S5, 21.4R3, 22.1R3, 22.2R1-S1, 22.2R2, 22.3R1, and all subsequent releases.

This issue is being tracked as PR 1653681 which is visible on the Customer Support website.

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

2023-10-11: 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-2023-44199 at cve.mitre.org
• https://supportportal.juniper.net/JSA73165 [juniper.net]