An MS-MPC or MS-MIC Service PIC may crash when large fragmented packets are passed through an Application Layer Gateway (ALG). Repeated crashes of the Service PC can result in an extended denial of service condition. The issue can be seen only if NAT or stateful-firewall rules are configured with ALGs enabled. This issue was caused by the code change for PR 1182910 in Junos OS 14.1X55-D30, 14.1X55-D35, 14.2R7, 15.1R5, and 16.1R2. No other versions of Junos OS and no other Juniper Networks products or platforms are affected by this issue. Affected releases are Juniper Networks Junos OS on MX platforms running: 14.1X55 from 14.1X55-D30 to releases prior to 14.1X55-D35; 14.2R from 14.2R7 to releases prior to 14.2R7-S4, 14.2R8; 15.1R from 15.1R5 to releases prior to 15.1R5-S2, 15.1R6; 16.1R from 16.1R2 to releases prior to 16.1R3-S2, 16.1R4.
| Software | From | Fixed in |
|---|---|---|
| juniper / junos | 14.1x55-d30 | 14.1x55-d30.x |
| juniper / junos | 14.1x55 | 14.1x55.x |
| juniper / junos | 14.2-r3 | 14.2-r3.x |
| juniper / junos | 14.2-r | 14.2-r.x |
| juniper / junos | 14.2-r7 | 14.2-r7.x |
| juniper / junos | 14.2-r4 | 14.2-r4.x |
| juniper / junos | 14.2-r1 | 14.2-r1.x |
| juniper / junos | 14.2-r2 | 14.2-r2.x |
| juniper / junos | 14.2-r6 | 14.2-r6.x |
| juniper / junos | 14.2-r5 | 14.2-r5.x |
| juniper / junos | 15.1-r | 15.1-r.x |
| juniper / junos | 15.1-r6 | 15.1-r6.x |
| juniper / junos | 15.1-r4 | 15.1-r4.x |
| juniper / junos | 15.1-r2 | 15.1-r2.x |
| juniper / junos | 15.1-r5 | 15.1-r5.x |
| juniper / junos | 15.1-r1 | 15.1-r1.x |
| juniper / junos | 15.1-r3 | 15.1-r3.x |
| juniper / junos | 16.1-r3 | 16.1-r3.x |
| juniper / junos | 16.1-r4 | 16.1-r4.x |
| juniper / junos | 16.1-r | 16.1-r.x |
| juniper / junos | 16.1-r1 | 16.1-r1.x |
| juniper / junos | 16.1-r2 | 16.1-r2.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.