CVE-2021-25928: 
JavaScript vulnerability analysis and mitigation

Prototype pollution vulnerability in 'safe-obj' versions 1.0.0 through 1.0.2 was discovered in April 2021. The vulnerability allows attackers to cause denial of service conditions and potentially achieve remote code execution. The issue affects the NPM module 'safe-obj' and stems from the expand() function's failure to validate object types before property assignment (WhiteSource).

The vulnerability exists in the expand() function which accepts obj, path, and thing as arguments. Due to the absence of validation on the path argument values, attackers can supply malicious values by including the proto property. The lack of validation before property assignment allows direct pollution of the Object prototype. The vulnerability has been assigned a CVSS v3.1 base score of 9.8 (CRITICAL) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (NVD).

Successful exploitation of this vulnerability can lead to denial of service conditions and potentially remote code execution. The vulnerability allows attackers to create non-existent properties or manipulate existing properties in the affected systems (WhiteSource).

Several mitigation strategies are available: 1) Freeze objects to prevent adding, removing, or changing properties, 2) Implement JSON input validation with schema validation to ensure only predefined attributes are allowed, 3) Use Object.create to create objects without prototype association. However, no fix version is currently available for the affected versions 1.0.0-1.0.2 (WhiteSource).