Swift Prometheus is a Swift client for the Prometheus monitoring system, supporting counters, gauges and histograms. In code which applies _un-sanitized string values into metric names or labels_, an attacker could make use of this and send a `?lang` query parameter containing newlines, `}` or similar characters which can lead to the attacker taking over the exported format -- including creating unbounded numbers of stored metrics, inflating server memory usage, or causing "bogus" metrics. This vulnerability is fixed in2.0.0-alpha.2.
https://github.com/swift-server/swift-prometheus/security/advisories/GHSA-x768-cvr2-345r
https://github.com/swift-server/swift-prometheus/commit/bfcd4bbfabe11aae4b035424ee9724582e288501