A vulnerability in Juniper Networks Junos OS on vMX and MX150 devices may allow an attacker to cause a Denial of Service (DoS) by sending specific packets requiring special processing in microcode that the flow cache can't handle, causing the riot forwarding daemon to crash. By continuously sending the same specific packets, an attacker can repeatedly crash the riot process causing a sustained Denial of Service. Flow cache is specific to vMX based products and the MX150, and is enabled by default in performance mode. This issue can only be triggered by traffic destined to the device. Transit traffic will not cause the riot daemon to crash. When the issue occurs, a core dump and riot log file entry are generated. For example: /var/crash/core.J-UKERN.mpc0.1557255993.3864.gz /home/pfe/RIOT logs: fpc0 riot[1888]: PANIC in lu_reorder_send_packet_postproc(): fpc0 riot[6655]: PANIC in lu_reorder_send_packet_postproc(): This issue affects Juniper Networks Junos OS: 18.1 versions prior to 18.1R3 on vMX and MX150; 18.2 versions prior to 18.2R3 on vMX and MX150; 18.2X75 versions prior to 18.2X75-D60 on vMX and MX150; 18.3 versions prior to 18.3R3 on vMX and MX150; 18.4 versions prior to 18.4R2 on vMX and MX150; 19.1 versions prior to 19.1R2 on vMX and MX150. This issue does not affect Junos OS versions prior to 18.1R1.
| Software | From | Fixed in |
|---|---|---|
| juniper / junos | 18.1-r2 | 18.1-r2.x |
| juniper / junos | 18.1 | 18.1.x |
| juniper / junos | 18.1-r2-s1 | 18.1-r2-s1.x |
| juniper / junos | 18.1-r2-s4 | 18.1-r2-s4.x |
| juniper / junos | 18.1-r2-s2 | 18.1-r2-s2.x |
| juniper / junos | 18.2-r1 | 18.2-r1.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 | 18.2-r2-s3 | 18.2-r2-s3.x |
| juniper / junos | 18.2-r2-s4 | 18.2-r2-s4.x |
| juniper / junos | 18.2-r1-s5 | 18.2-r1-s5.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 | 18.2x75 | 18.2x75.x |
| juniper / junos | 18.2x75-d20 | 18.2x75-d20.x |
| juniper / junos | 18.2x75-d40 | 18.2x75-d40.x |
| juniper / junos | 18.2x75-d30 | 18.2x75-d30.x |
| juniper / junos | 18.3-r1-s5 | 18.3-r1-s5.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 | 18.3-r1-s3 | 18.3-r1-s3.x |
| juniper / junos | 18.3-r1-s2 | 18.3-r1-s2.x |
| juniper / junos | 18.3 | 18.3.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 | 18.4.x |
| juniper / junos | 18.4-r1-s5 | 18.4-r1-s5.x |
| juniper / junos | 18.4-r1-s1 | 18.4-r1-s1.x |
| juniper / junos | 18.4-r1 | 18.4-r1.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 | 19.1-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 |
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.