Vulnerability Database

346,508

Total vulnerabilities in the database

CVE-2024-21587 — juniper / junos

Improper Handling of Exceptional Conditions

An Improper Handling of Exceptional Conditions vulnerability in the broadband edge subscriber management daemon (bbe-smgd) of Juniper Networks Junos OS on MX Series allows an attacker directly connected to the vulnerable system who repeatedly flaps DHCP subscriber sessions to cause a slow memory leak, ultimately leading to a Denial of Service (DoS). Memory can only be recovered by manually restarting bbe-smgd.

This issue only occurs if BFD liveness detection for DHCP subscribers is enabled. Systems without BFD liveness detection enabled are not vulnerable to this issue.

Indication of the issue can be observed by periodically executing the 'show system processes extensive' command, which will indicate an increase in memory allocation for bbe-smgd. A small amount of memory is leaked every time a DHCP subscriber logs in, which will become visible over time, ultimately leading to memory starvation.

user@junos> show system processes extensive | match bbe-smgd 13071 root 24 0 415M 201M select 0 0:41 7.28% bbe-smgd{bbe-smgd} 13071 root 20 0 415M 201M select 1 0:04 0.00% bbe-smgd{bbe-smgd} ... user@junos> show system processes extensive | match bbe-smgd 13071 root 20 0 420M 208M select 0 4:33 0.10% bbe-smgd{bbe-smgd} 13071 root 20 0 420M 208M select 0 0:12 0.00% bbe-smgd{bbe-smgd} ... This issue affects Juniper Networks Junos OS on MX Series:

  • All versions earlier than 20.4R3-S9;
  • 21.2 versions earlier than 21.2R3-S7;
  • 21.3 versions earlier than 21.3R3-S5;
  • 21.4 versions earlier than 21.4R3-S5;
  • 22.1 versions earlier than 22.1R3-S4;
  • 22.2 versions earlier than 22.2R3-S3;
  • 22.3 versions earlier than 22.3R3-S2;
  • 22.4 versions earlier than 22.4R2-S2, 22.4R3;
  • 23.2 versions earlier than 23.2R1-S1, 23.2R2.
  • Published: Jan 12, 2024
  • Updated: Nov 16, 2025
  • CVE: CVE-2024-21587
  • Severity: Medium
  • Exploit:

CVSS v3:

  • Severity: Medium
  • Score: 6.5
  • AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWEs:

Software From Fixed in
juniper / junos 20.4-r1 20.4-r1.x
juniper / junos 20.4-r1-s1 20.4-r1-s1.x
juniper / junos 20.4-r2 20.4-r2.x
juniper / junos 20.4-r2-s1 20.4-r2-s1.x
juniper / junos 20.4-r3 20.4-r3.x
juniper / junos 20.4 20.4.x
juniper / junos 20.4-r3-s1 20.4-r3-s1.x
juniper / junos 20.4-r2-s2 20.4-r2-s2.x
juniper / junos 20.4-r3-s2 20.4-r3-s2.x
juniper / junos 20.4-r3-s3 20.4-r3-s3.x
juniper / junos 20.4-r3-s4 20.4-r3-s4.x
juniper / junos 20.4-r3-s5 20.4-r3-s5.x
juniper / junos 20.4-r3-s7 20.4-r3-s7.x
juniper / junos 20.4-r3-s6 20.4-r3-s6.x
juniper / junos 20.4-r3-s8 20.4-r3-s8.x
juniper / junos 21.2-r3-s5 21.2-r3-s5.x
juniper / junos 21.2-r3-s6 21.2-r3-s6.x
juniper / junos 21.2-r3-s4 21.2-r3-s4.x
juniper / junos 21.2-r3-s3 21.2-r3-s3.x
juniper / junos 21.2-r3-s2 21.2-r3-s2.x
juniper / junos 21.2-r3-s1 21.2-r3-s1.x
juniper / junos 21.2-r2 21.2-r2.x
juniper / junos 21.2-r3 21.2-r3.x
juniper / junos 21.2 21.2.x
juniper / junos 21.2-r1-s2 21.2-r1-s2.x
juniper / junos 21.2-r2-s1 21.2-r2-s1.x
juniper / junos 21.2-r2-s2 21.2-r2-s2.x
juniper / junos 21.2-r1-s1 21.2-r1-s1.x
juniper / junos 21.2-r1 21.2-r1.x
juniper / junos 21.3-r1 21.3-r1.x
juniper / junos 21.3-r2 21.3-r2.x
juniper / junos 21.3-r1-s1 21.3-r1-s1.x
juniper / junos 21.3-r1-s2 21.3-r1-s2.x
juniper / junos 21.3-r2-s1 21.3-r2-s1.x
juniper / junos 21.3-r2-s2 21.3-r2-s2.x
juniper / junos 21.3-r3 21.3-r3.x
juniper / junos 21.3-r3-s1 21.3-r3-s1.x
juniper / junos 21.3 21.3.x
juniper / junos 21.3-r3-s2 21.3-r3-s2.x
juniper / junos 21.3-r3-s3 21.3-r3-s3.x
juniper / junos 21.3-r3-s4 21.3-r3-s4.x
juniper / junos 21.4-r3-s3 21.4-r3-s3.x
juniper / junos 21.4-r3-s2 21.4-r3-s2.x
juniper / junos 21.4-r3-s1 21.4-r3-s1.x
juniper / junos 21.4 21.4.x
juniper / junos 21.4-r3 21.4-r3.x
juniper / junos 21.4-r2-s2 21.4-r2-s2.x
juniper / junos 21.4-r2 21.4-r2.x
juniper / junos 21.4-r2-s1 21.4-r2-s1.x
juniper / junos 21.4-r1-s2 21.4-r1-s2.x
juniper / junos 21.4-r1 21.4-r1.x
juniper / junos 21.4-r1-s1 21.4-r1-s1.x
juniper / junos 21.4-r3-s4 21.4-r3-s4.x
juniper / junos 22.1-r3-s3 22.1-r3-s3.x
juniper / junos 22.1 22.1.x
juniper / junos 22.1-r1 22.1-r1.x
juniper / junos 22.1-r1-s2 22.1-r1-s2.x
juniper / junos 22.1-r2-s2 22.1-r2-s2.x
juniper / junos 22.1-r1-s1 22.1-r1-s1.x
juniper / junos 22.1-r2 22.1-r2.x
juniper / junos 22.1-r3-s1 22.1-r3-s1.x
juniper / junos 22.1-r3 22.1-r3.x
juniper / junos 22.1-r3-s2 22.1-r3-s2.x
juniper / junos 22.1-r2-s1 22.1-r2-s1.x
juniper / junos 22.2-r3-s1 22.2-r3-s1.x
juniper / junos 22.2-r2-s2 22.2-r2-s2.x
juniper / junos 22.2-r3 22.2-r3.x
juniper / junos 22.2-r1-s2 22.2-r1-s2.x
juniper / junos 22.2-r2-s1 22.2-r2-s1.x
juniper / junos 22.2-r2 22.2-r2.x
juniper / junos 22.2-r1 22.2-r1.x
juniper / junos 22.2-r1-s1 22.2-r1-s1.x
juniper / junos 22.2 22.2.x
juniper / junos 22.2-r3-s2 22.2-r3-s2.x
juniper / junos 22.3-r3 22.3-r3.x
juniper / junos 22.3-r2-s2 22.3-r2-s2.x
juniper / junos 22.3 22.3.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-r1 22.3-r1.x
juniper / junos 22.3-r1-s2 22.3-r1-s2.x
juniper / junos 22.3-r1-s1 22.3-r1-s1.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-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 22.4.x
juniper / junos 22.4-r2-s1 22.4-r2-s1.x
juniper / junos 23.2-r1 23.2-r1.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.