A vulnerability in Juniper Networks Junos OS caused by Missing Release of Memory after Effective Lifetime leads to a memory leak each time the CLI command 'show system connections extensive' is executed. The amount of memory leaked on each execution depends on the number of TCP connections from and to the system. Repeated execution will cause more memory to leak and eventually daemons that need to allocate additionally memory and ultimately the kernel to crash, which will result in traffic loss. Continued execution of this command will cause a sustained Denial of Service (DoS) condition. An administrator can use the following CLI command to monitor for increase in memory consumption of the netstat process, if it exists: user@junos> show system processes extensive | match "username|netstat" PID USERNAME PRI NICE SIZE RES STATE C TIME WCPU COMMAND 21181 root 100 0 5458M 4913M CPU3 2 0:59 97.27% netstat The following log message might be observed if this issue happens: kernel: %KERN-3: pid 21181 (netstat), uid 0, was killed: out of swap space This issue affects Juniper Networks Junos OS 18.2 versions prior to 18.2R2-S8, 18.2R3-S7. 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S6, 18.4R3-S7; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S4; 19.2 versions prior to 19.2R1-S6, 19.2R3-S2; 19.3 versions prior to 19.3R2-S6, 19.3R3-S1; 19.4 versions prior to 19.4R1-S4, 19.4R2-S3, 19.4R3-S1; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R2-S1, 20.2R3; 20.3 versions prior to 20.3R1-S1, 20.3R2; This issue does not affect Juniper Networks Junos OS versions prior to 18.2R1.
| Software | From | Fixed in |
|---|---|---|
| juniper / junos | 18.2-r1 | 18.2-r1.x |
| juniper / junos | 18.2 | 18.2.x |
| juniper / junos | 18.2-r2-s1 | 18.2-r2-s1.x |
| juniper / junos | 18.2-r2-s2 | 18.2-r2-s2.x |
| juniper / junos | 18.2-r1-s3 | 18.2-r1-s3.x |
| juniper / junos | 18.3-r1-s1 | 18.3-r1-s1.x |
| juniper / junos | 18.3-r2 | 18.3-r2.x |
| juniper / junos | 18.3-r1 | 18.3-r1.x |
| juniper / junos | 18.4-r1 | 18.4-r1.x |
| juniper / junos | 18.3-r1-s2 | 18.3-r1-s2.x |
| juniper / junos | 18.3 | 18.3.x |
| juniper / junos | 18.4 | 18.4.x |
| juniper / junos | 18.4-r1-s1 | 18.4-r1-s1.x |
| juniper / junos | 18.3-r1-s3 | 18.3-r1-s3.x |
| juniper / junos | 18.2-r2-s3 | 18.2-r2-s3.x |
| juniper / junos | 18.2-r2-s4 | 18.2-r2-s4.x |
| juniper / junos | 18.3-r1-s4 | 18.3-r1-s4.x |
| juniper / junos | 18.2-r1-s4 | 18.2-r1-s4.x |
| juniper / junos | 18.2-r1-s5 | 18.2-r1-s5.x |
| juniper / junos | 18.2-r2 | 18.2-r2.x |
| juniper / junos | 18.4-r1-s3 | 18.4-r1-s3.x |
| juniper / junos | 18.4-r1-s4 | 18.4-r1-s4.x |
| juniper / junos | 18.4-r1-s2 | 18.4-r1-s2.x |
| juniper / junos | 19.1-r1 | 19.1-r1.x |
| juniper / junos | 19.1 | 19.1.x |
| juniper / junos | 19.2-r1 | 19.2-r1.x |
| juniper / junos | 18.4-r2 | 18.4-r2.x |
| juniper / junos | 18.2-r3 | 18.2-r3.x |
| juniper / junos | 19.1-r1-s1 | 19.1-r1-s1.x |
| juniper / junos | 19.1-r1-s3 | 19.1-r1-s3.x |
| juniper / junos | 19.1-r1-s2 | 19.1-r1-s2.x |
| juniper / junos | 18.2-r2-s5 | 18.2-r2-s5.x |
| juniper / junos | 18.2-r2-s6 | 18.2-r2-s6.x |
| juniper / junos | 18.4-r1-s5 | 18.4-r1-s5.x |
| juniper / junos | 19.2-r1-s1 | 19.2-r1-s1.x |
| juniper / junos | 19.2-r1-s2 | 19.2-r1-s2.x |
| juniper / junos | 18.3-r1-s5 | 18.3-r1-s5.x |
| juniper / junos | 18.2-r3-s1 | 18.2-r3-s1.x |
| juniper / junos | 18.3-r2-s1 | 18.3-r2-s1.x |
| juniper / junos | 18.3-r2-s2 | 18.3-r2-s2.x |
| juniper / junos | 18.4-r2-s1 | 18.4-r2-s1.x |
| juniper / junos | 19.3 | 19.3.x |
| juniper / junos | 19.3-r1 | 19.3-r1.x |
| juniper / junos | 19.2 | 19.2.x |
| juniper / junos | 18.4-r2-s2 | 18.4-r2-s2.x |
| juniper / junos | 18.3-r1-s6 | 18.3-r1-s6.x |
| juniper / junos | 18.2-r3-s2 | 18.2-r3-s2.x |
| juniper / junos | 19.2-r1-s3 | 19.2-r1-s3.x |
| juniper / junos | 18.3-r3 | 18.3-r3.x |
| juniper / junos | 19.4-r1 | 19.4-r1.x |
| juniper / junos | 19.3-r2 | 19.3-r2.x |
| juniper / junos | 19.1-r2 | 19.1-r2.x |
| juniper / junos | 18.4-r3 | 18.4-r3.x |
| juniper / junos | 18.4-r2-s3 | 18.4-r2-s3.x |
| juniper / junos | 18.3-r3-s1 | 18.3-r3-s1.x |
| juniper / junos | 19.3-r2-s1 | 19.3-r2-s1.x |
| juniper / junos | 19.3-r1-s1 | 19.3-r1-s1.x |
| juniper / junos | 19.2-r1-s4 | 19.2-r1-s4.x |
| juniper / junos | 20.1-r1 | 20.1-r1.x |
| juniper / junos | 19.4-r1-s1 | 19.4-r1-s1.x |
| juniper / junos | 19.3-r2-s2 | 19.3-r2-s2.x |
| juniper / junos | 19.1-r1-s4 | 19.1-r1-s4.x |
| juniper / junos | 18.4-r1-s6 | 18.4-r1-s6.x |
| juniper / junos | 18.3-r2-s3 | 18.3-r2-s3.x |
| juniper / junos | 18.2-r3-s3 | 18.2-r3-s3.x |
| juniper / junos | 18.2-r3-s4 | 18.2-r3-s4.x |
| juniper / junos | 18.4-r3-s2 | 18.4-r3-s2.x |
| juniper / junos | 18.4-r3-s1 | 18.4-r3-s1.x |
| juniper / junos | 18.4-r2-s4 | 18.4-r2-s4.x |
| juniper / junos | 19.1-r2-s1 | 19.1-r2-s1.x |
| juniper / junos | 19.1-r3-s1 | 19.1-r3-s1.x |
| juniper / junos | 19.4-r1-s2 | 19.4-r1-s2.x |
| juniper / junos | 20.1-r1-s1 | 20.1-r1-s1.x |
| juniper / junos | 20.2-r1 | 20.2-r1.x |
| juniper / junos | 20.1-r1-s2 | 20.1-r1-s2.x |
| juniper / junos | 20.1-r1-s3 | 20.1-r1-s3.x |
| juniper / junos | 19.4-r2 | 19.4-r2.x |
| juniper / junos | 19.4-r2-s1 | 19.4-r2-s1.x |
| juniper / junos | 19.3-r2-s3 | 19.3-r2-s3.x |
| juniper / junos | 19.1-r3-s2 | 19.1-r3-s2.x |
| juniper / junos | 18.4-r3-s3 | 18.4-r3-s3.x |
| juniper / junos | 18.4-r3-s4 | 18.4-r3-s4.x |
| juniper / junos | 18.2-r3-s5 | 18.2-r3-s5.x |
| juniper / junos | 18.3-r3-s2 | 18.3-r3-s2.x |
| juniper / junos | 19.2-r2 | 19.2-r2.x |
| juniper / junos | 18.3-r2-s4 | 18.3-r2-s4.x |
| juniper / junos | 19.3-r2-s4 | 19.3-r2-s4.x |
| juniper / junos | 18.3-r3-s3 | 18.3-r3-s3.x |
| juniper / junos | 20.2-r1-s1 | 20.2-r1-s1.x |
| juniper / junos | 20.2-r1-s2 | 20.2-r1-s2.x |
| juniper / junos | 19.4-r2-s2 | 19.4-r2-s2.x |
| juniper / junos | 19.2-r3 | 19.2-r3.x |
| juniper / junos | 18.4-r3-s5 | 18.4-r3-s5.x |
| juniper / junos | 19.4-r3 | 19.4-r3.x |
| juniper / junos | 19.3-r2-s5 | 19.3-r2-s5.x |
| juniper / junos | 19.3-r3 | 19.3-r3.x |
| juniper / junos | 19.2-r1-s5 | 19.2-r1-s5.x |
| juniper / junos | 19.1-r3-s3 | 19.1-r3-s3.x |
| juniper / junos | 18.4-r2-s5 | 18.4-r2-s5.x |
| juniper / junos | 19.1-r1-s5 | 19.1-r1-s5.x |
| juniper / junos | 18.4-r1-s7 | 18.4-r1-s7.x |
| juniper / junos | 20.3-r1 | 20.3-r1.x |
| juniper / junos | 18.2-r2-s7 | 18.2-r2-s7.x |
| juniper / junos | 19.2-r2-s1 | 19.2-r2-s1.x |
| juniper / junos | 18.2-r3-s6 | 18.2-r3-s6.x |
| juniper / junos | 18.2-r1-s2 | 18.2-r1-s2.x |
| juniper / junos | 20.1-r1-s4 | 20.1-r1-s4.x |
| juniper / junos | 18.4-r3-s6 | 18.4-r3-s6.x |
| juniper / junos | 20.2-r1-s3 | 20.2-r1-s3.x |
| juniper / junos | 19.2-r3-s1 | 19.2-r3-s1.x |
| juniper / junos | 20.2-r2 | 20.2-r2.x |
| juniper / junos | 19.4-r1-s3 | 19.4-r1-s3.x |
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.