Vulnerability Database

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Total vulnerabilities in the database

CVE-2024-39518 — juniper / junos

Out-of-bounds Write

A Heap-based Buffer Overflow vulnerability in the telemetry sensor process (sensord) of Juniper Networks Junos OS on MX240, MX480, MX960 platforms using MPC10E causes a steady increase in memory utilization, ultimately leading to a Denial of Service (DoS).

When the device is subscribed to a specific subscription on Junos Telemetry Interface, a slow memory leak occurs and eventually all resources are consumed and the device becomes unresponsive. A manual reboot of the Line Card will be required to restore the device to its normal functioning. 

This issue is only seen when telemetry subscription is active.

The Heap memory utilization can be monitored using the following command:   > show system processes extensive

The following command can be used to monitor the memory utilization of the specific sensor   > show system info | match sensord PID NAME MEMORY PEAK MEMORY %CPU THREAD-COUNT CORE-AFFINITY UPTIME

1986 sensord 877.57MB 877.57MB 2 4 0,2-15 7-21:41:32

This issue affects Junos OS: 

  • from 21.2R3-S5 before 21.2R3-S7, 
  • from 21.4R3-S4 before 21.4R3-S6, 
  • from 22.2R3 before 22.2R3-S4, 
  • from 22.3R2 before 22.3R3-S2, 
  • from 22.4R1 before 22.4R3, 
  • from 23.2R1 before 23.2R2.
  • Published: Jul 10, 2024
  • Updated: Nov 16, 2025
  • CVE: CVE-2024-39518
  • Severity: High
  • Exploit:

CVSS v3:

  • Severity: High
  • Score: 7.5
  • AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Software From Fixed in
juniper / junos 21.2-r3-s5 21.2-r3-s5.x
juniper / junos 21.2-r3-s6 21.2-r3-s6.x
juniper / junos 21.4-r3-s4 21.4-r3-s4.x
juniper / junos 21.4-r3-s5 21.4-r3-s5.x
juniper / junos 22.2-r3-s1 22.2-r3-s1.x
juniper / junos 22.2-r3-s2 22.2-r3-s2.x
juniper / junos 22.2-r3 22.2-r3.x
juniper / junos 22.2-r3-s3 22.2-r3-s3.x
juniper / junos 22.3-r3-s1 22.3-r3-s1.x
juniper / junos 22.3-r2 22.3-r2.x
juniper / junos 22.3-r2-s2 22.3-r2-s2.x
juniper / junos 22.3-r3 22.3-r3.x
juniper / junos 22.3-r2-s1 22.3-r2-s1.x
juniper / junos 22.4-r2 22.4-r2.x
juniper / junos 22.4-r2-s1 22.4-r2-s1.x
juniper / junos 22.4-r1 22.4-r1.x
juniper / junos 22.4-r1-s1 22.4-r1-s1.x
juniper / junos 22.4-r1-s2 22.4-r1-s2.x
juniper / junos 22.4-r2-s2 22.4-r2-s2.x
juniper / junos 23.2-r1-s2 23.2-r1-s2.x
juniper / junos 23.2-r1 23.2-r1.x
juniper / junos 23.2-r1-s1 23.2-r1-s1.x

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.