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:

show heap
shows an increase in "LAN buffer" utilization and

show clksync ptp nbr-upd-info
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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2024-21599
• https://supportportal.juniper.net/JSA75740
• https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L