An Improper Neutralization of Data within XPath Expressions (XPath Injection) vulnerability in J-Web shipped with Juniper Networks Junos OS allows an unauthenticated, network-based attacker to execute remote commands on the target device.
While an administrator is logged into a J-Web session or has previously logged in and subsequently logged out of their J-Web session, the attacker can arbitrarily execute commands on the target device with the other users credentials. In the worst case, the attacker will have full control over the device. This issue affects Junos OS:
The product uses external input to dynamically construct an XPath expression used to retrieve data from an XML database, but it does not neutralize or incorrectly neutralizes that input. This allows an attacker to control the structure of the query.