Which CVSSv3 metric value increases when the attacker is able to modify all files protected by the vulnerable component?

Confidentiality measures the impact of unauthorized information disclosure, not modification of data.

In CVSSv3, the Integrity metric specifically measures the impact to the integrity of information resources, meaning unauthorized modification of data. When an attacker can modify all files protected by the vulnerable component, the Integrity impact is rated High (H), which directly increases the overall CVSS score.

Availability measures the impact on access to the affected component or resource, such as service disruption or denial, not data modification.

Attack Complexity is an exploitability metric describing conditions beyond the attacker's control, not an impact metric related to what data is affected.