CVE intelligence and bounded remediation

CVE-2024-39517 — Juniper Junos security vulnerability

High CVSS 7.1

An Improper Check for Unusual or Exceptional Conditions vulnerability in the Layer 2 Address Learning Daemon (l2ald) on Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker to cause Denial of Service (DoS). In an EVPN/VXLAN scenario, when a high amount specific Layer 2 packets are processed by the device, it can cause the Routing Protocol Daemon (rpd) to utilize all CPU resources which causes the device to hang. A manual restart of the rpd is required to restore services. This issue affects both IPv4 and IPv6 implementations. This issue affects Junos OS: All versions earlier than 21.4R3-S7; 22.1 versions earlier than 22.1R3-S5; 22.2 versions earlier than 22.2R3-S3; 22.3 versions earlier than 22.3R3-S3; 22.4 versions earlier than 22.4R3-S2; 23.2 versions earlier than 23.2R2; 23.4 versions earlier than 23.4R1-S1. Junos OS Evolved: All versions earlier than 21.4R3-S7-EVO; 22.1-EVO versions earlier than 22.1R3-S5-EVO; 22.2-EVO versions earlier than 22.2R3-S3-EVO; 22.3-EVO versions earlier than 22.3R3-S3-EVO; 22.4-EVO versions earlier than 22.4R3-S2-EVO; 23.2-EVO versions earlier than 23.2R2-EVO; 23.4-EVO versions earlier than 23.4R1-S1-EVO, 23.4R…

Severity
High
CVSS
7.1 (4.0)
Published
2024-07-10
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-754

Affected products

  • juniper / junos
  • juniper / junos / 21.4

Showing 2 representative product identities from 123 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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