matrix-react-sdk is a Matrix chat protocol SDK for React Javascript. In certain configurations, data sent by remote servers containing special strings in key locations could cause modifications of the `Object.prototype`, disrupting matrix-react-sdk functionality, causing denial of service and potentially affecting program logic. This is fixed in matrix-react-sdk 3.69.0 and users are advised to upgrade. There are no known workarounds for this vulnerability. Note this advisory is distinct from GHSA-2x9c-qwgf-94xr which refers to a similar issue.