The improper handling of client-side parameters in J-Web of Juniper Networks Junos OS allows an attacker to perform a number of different malicious actions against a target device when a user is authenticated to J-Web. An attacker may be able to supersede existing parameters, including hardcoded parameters within the HTTP/S session, access and exploit variables, bypass web application firewall rules or input validation mechanisms, and otherwise alter and modify J-Web's normal behavior. An attacker may be able to transition victims to malicious web services, or exfiltrate sensitive information from otherwise secure web forms. This issue affects: Juniper Networks Junos OS: All versions prior to 17.4R3-S3.

18.1 versions prior to 18.1R3-S12.

18.2 versions prior to 18.2R3-S6.

18.3 versions prior to 18.3R3-S4.

18.4 versions prior to 18.4R3-S6.

19.1 versions prior to 19.1R3-S4.

19.2 versions prior to 19.2R3-S1.

19.3 versions prior to 19.3R3-S1.

19.4 versions prior to 19.4R2-S2, 19.4R3.

20.1 versions prior to 20.1R2.

20.2 versions prior to 20.2R2.