CVE-2020-25739: 
Ruby vulnerability analysis and mitigation

An issue was discovered in the gon gem before version 6.4.0 for Ruby, identified as CVE-2020-25739. The vulnerability was related to MultiJson not honoring the escape_mode parameter to escape fields as an XSS protection mechanism. The issue was disclosed in September 2020 and affected Ruby applications using the gon library to send data to JavaScript (NVD).

The vulnerability has a CVSS v3.1 Base Score of 6.1 (MEDIUM) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N. The issue was classified as CWE-79 (Improper Neutralization of Input During Web Page Generation - Cross-site Scripting). The vulnerability stemmed from improper escaping of certain input in the JSON dumper component (NVD).

The vulnerability could allow an attacker to execute cross-site scripting (XSS) attacks due to improper input escaping. This could potentially lead to unauthorized access to sensitive information or execution of malicious code in the context of the user's browser (Ubuntu Security).

The vulnerability requires network access and user interaction to be exploited. An attacker could leverage the lack of proper escaping to execute cross-site scripting attacks against users of applications using the vulnerable gon gem versions (NVD).

The vulnerability was fixed in gon version 6.4.0, which implements proper escaping for XSS protection by default without relying on MultiJson. The fix involves modifying json_dumper.rb to handle escaping internally. Users should upgrade to version 6.4.0 or later to address this vulnerability (Gon Commit).