CVE intelligence and bounded remediation

CVE-2024-21599 — Juniper Junos security vulnerability

Medium CVSS 6.5

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.

Severity
Medium
CVSS
6.5 (3.1)
Published
2024-01-12
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-401

Affected products

  • juniper / junos / 20.4
  • juniper / junos / 21.1

Showing 2 representative product identities from 39 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Resource exhaustion and denial of service

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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