Update Severity Rating

Set the severity rating (the ZeroPath score label shown on the issue) of a single issue, e.g. downgrade a "High" to "Medium". Use this when a user asks to reassess or change an issue's severity by label. The rating is one of "critical", "high", "medium", "low", or "info" ("medium" is displayed as "Medium"/"Moderate"). The ZeroPath score is the composite of the raw severity and the scanner's confidence, so this endpoint adjusts the underlying severity to land the score in the requested band, recording the confidence it scored with. Prefer this over updateSeverity whenever you want the displayed rating to change: updateSeverity sets only the raw 0-10 number, which cannot lift a finding with no recorded confidence out of the Informational band. Because confidence caps the maximum reachable score, rating a low-confidence finding up into a high band can be rejected; downgrades always apply.