A Missing Release of Memory after Effective Lifetime vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX Series allows an adjacent, unauthenticated attacker to cause a Denial of Service (DoS).

If an MX Series device receives PTP packets on an MPC3E that doesn't support PTP this causes a memory leak which will result in unpredictable behavior and ultimately in an MPC crash and restart.

To monitor for this issue, please use the following FPC vty level commands:

shows an increase in "LAN buffer" utilization and

shows non-zero "Pending PFEs" counter.

This issue affects Juniper Networks Junos OS on MX Series with MPC3E:

• All versions earlier than 20.4R3-S3;
• 21.1 versions earlier than 21.1R3-S4;
• 21.2 versions earlier than 21.2R3;
• 21.3 versions earlier than 21.3R2-S1, 21.3R3;
• 21.4 versions earlier than 21.4R2;
• 22.1 versions earlier than 22.1R2.

To be affected by this issue an interface on the MPC needs to be configured with PTP as follows:

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-2024-21599.

The following software releases have been updated to resolve this specific issue: 20.4R3-S3, 21.1R3-S4, 21.2R3, 21.3R2-S1, 21.3R3, 21.4R2, 22.1R2, 22.2R1, and all subsequent releases.

This issue is being tracked as PR 1646324 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).

2024-01-10: 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-2024-21599 at cve.mitre.org