Insufficient Cross-Site Scripting (XSS) protection in Juniper Networks J-Web and web based (HTTP/HTTPS) services allows an unauthenticated attacker to hijack the target user's HTTP/HTTPS session and perform administrative actions on the Junos device as the targeted user. This issue only affects Juniper Networks Junos OS devices with HTTP/HTTPS services enabled such as J-Web, Web Authentication, Dynamic-VPN (DVPN), Firewall Authentication Pass-Through with Web-Redirect, and Zero Touch Provisioning (ZTP). Junos OS devices with HTTP/HTTPS services disabled are not affected. If HTTP/HTTPS services are enabled, the following command will show the httpd processes: user@device> show system processes | match http 5260 - S 0:00.13 /usr/sbin/httpd-gk -N 5797 - I 0:00.10 /usr/sbin/httpd --config /jail/var/etc/httpd.conf In order to successfully exploit this vulnerability, the attacker needs to convince the device administrator to take action such as clicking the crafted URL sent via phishing email or convince the administrator to input data in the browser console. This issue affects Juniper Networks Junos OS: 18.1 versions prior to 18.1R3-S1; 18.2 versions prior to 18.2R3-S5; 18.3 versions prior to 18.3R2-S4, 18.3R3-S2; 18.4 versions prior to 18.4R2-S5, 18.4R3-S2; 19.1 versions prior to 19.1R2-S2, 19.1R3-S1; 19.2 versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S4, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2; 20.1 versions prior to 20.1R1-S2, 20.1R2. This issue does not affect Juniper Networks Junos OS prior to 18.1R1.
| Software | From | Fixed in |
|---|---|---|
| juniper / junos | 18.1-r1 | 18.1-r1.x |
| juniper / junos | 18.1-r3 | 18.1-r3.x |
| juniper / junos | 18.1-r2 | 18.1-r2.x |
| 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 | 18.1-r2-s2 | 18.1-r2-s2.x |
| juniper / junos | 18.4-r1 | 18.4-r1.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 | 18.3-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 | 18.2-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-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-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 | 19.1-r3.x |
| juniper / junos | 19.4-r1-s2 | 19.4-r1-s2.x |
| juniper / junos | 19.3-r2-s3 | 19.3-r2-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.