diff --git a/change/@fluentui-react-charting-7ab29f8a-39ad-4df2-a902-360f3961bbf2.json b/change/@fluentui-react-charting-7ab29f8a-39ad-4df2-a902-360f3961bbf2.json
new file mode 100644
index 0000000000000..43fb63d835840
--- /dev/null
+++ b/change/@fluentui-react-charting-7ab29f8a-39ad-4df2-a902-360f3961bbf2.json
@@ -0,0 +1,6 @@
+{
+  "type": "patch",
+  "comment": "fix: prevent prototype pollution in SankeyChart node ID maps.",
+  "packageName": "@fluentui/react-charting",
+  "email": "paulmardling@microsoft.com"
+}
diff --git a/change/@fluentui-react-charts-74a9389f-5fc5-45cf-b170-ae0c14afed64.json b/change/@fluentui-react-charts-74a9389f-5fc5-45cf-b170-ae0c14afed64.json
new file mode 100644
index 0000000000000..e99d10d41c6d3
--- /dev/null
+++ b/change/@fluentui-react-charts-74a9389f-5fc5-45cf-b170-ae0c14afed64.json
@@ -0,0 +1,6 @@
+{
+  "type": "patch",
+  "comment": "fix: prevent prototype pollution in SankeyChart node ID maps.",
+  "packageName": "@fluentui/react-charts",
+  "email": "paulmardling@microsoft.com"
+}
diff --git a/packages/charts/react-charting/src/components/SankeyChart/SankeyChart.base.tsx b/packages/charts/react-charting/src/components/SankeyChart/SankeyChart.base.tsx
index 1d0a350519f9f..de5848b8ede61 100644
--- a/packages/charts/react-charting/src/components/SankeyChart/SankeyChart.base.tsx
+++ b/packages/charts/react-charting/src/components/SankeyChart/SankeyChart.base.tsx
@@ -39,7 +39,7 @@ type NodeValues = ItemValues<number>;
 type LinkItemValues<T> = { [key: NodeId]: ItemValues<T> };
 type LinkValues = LinkItemValues<number>;
 
-type NodesInColumns = { [key: number]: SNode[] };
+type NodesInColumns = ItemValues<SNode[]>;
 type NormalizedData = ISankeyChartData & {
   width: number;
   height: number;
@@ -56,6 +56,10 @@ type NormalizeDiagramFunction = (
 type NodeColors = { fillColor: string; borderColor: string };
 type SankeyLayoutGenerator = SankeyLayout<SankeyGraph<{}, {}>, {}, {}>;
 
+function createNodeIdMap<T>(): ItemValues<T> {
+  return Object.setPrototypeOf({}, null);
+}
+
 export interface ISankeyChartState extends IBasestate, IChartHoverCardProps {
   containerWidth: number;
   containerHeight: number;
@@ -194,7 +198,7 @@ function getSelectedLinksforStreamHover(singleLink: SLink): {
  */
 // This is exported for unit tests.
 export function groupNodesByColumn(graph: ISankeyChartData): NodesInColumns {
-  const nodesInColumn: NodesInColumns = {};
+  const nodesInColumn = createNodeIdMap<SNode[]>();
   graph.nodes.forEach((node: SNode) => {
     const columnId = node.layer!;
     if (nodesInColumn[columnId]) {
@@ -331,7 +335,7 @@ function duplicateData(data: ISankeyChartData): ISankeyChartData {
 }
 
 function valuesOfNodes(nodes: SNode[]): NodeValues {
-  const result: NodeValues = {};
+  const result = createNodeIdMap<number>();
   nodes.forEach((node: SNode) => {
     result[node.nodeId as NodeId] = node.value!;
   });
@@ -339,12 +343,12 @@ function valuesOfNodes(nodes: SNode[]): NodeValues {
 }
 
 function valuesOfLinks(links: SLink[]): LinkValues {
-  const result: LinkValues = {};
+  const result = createNodeIdMap<ItemValues<number>>();
   links.forEach((link: SLink) => {
     const sourceId = idFromNumberOrSNode(link.source);
     let sourceToTarget = result[sourceId];
     if (!sourceToTarget) {
-      sourceToTarget = {};
+      sourceToTarget = createNodeIdMap<number>();
       result[sourceId] = sourceToTarget;
     }
     sourceToTarget[idFromNumberOrSNode(link.target)] = link.value;
@@ -495,12 +499,12 @@ function computeLinkAttributes(
   linkFrom: (node: SNode) => string,
   linkAriaLabel: (link: SLink) => string,
 ): LinkItemValues<RenderedLinkAttributes> {
-  const result: LinkItemValues<RenderedLinkAttributes> = {};
+  const result = createNodeIdMap<ItemValues<RenderedLinkAttributes>>();
   links.forEach((link: SLink) => {
     const sourceId = idFromNumberOrSNode(link.source);
     let sourceToTarget = result[sourceId];
     if (!sourceToTarget) {
-      sourceToTarget = {};
+      sourceToTarget = createNodeIdMap<RenderedLinkAttributes>();
       result[sourceId] = sourceToTarget;
     }
     sourceToTarget[idFromNumberOrSNode(link.target)] = {
@@ -928,7 +932,7 @@ export class SankeyChartBase extends React.Component<ISankeyChartProps, ISankeyC
     nodes: SNode[],
     nodeAriaLabel: (node: SNode, weight: number) => string,
   ): ItemValues<RenderedNodeAttributes> {
-    const result: ItemValues<RenderedNodeAttributes> = {};
+    const result = createNodeIdMap<RenderedNodeAttributes>();
     const weightSpan = select('.nodeName').append('text').attr('class', 'tempText').append('tspan').text(null);
     const nameSpan = select('.nodeName')
       .append('text')
diff --git a/packages/charts/react-charting/src/components/SankeyChart/SankeyChart.test.tsx b/packages/charts/react-charting/src/components/SankeyChart/SankeyChart.test.tsx
index 3e4baa0e246b3..ce379eb02859b 100644
--- a/packages/charts/react-charting/src/components/SankeyChart/SankeyChart.test.tsx
+++ b/packages/charts/react-charting/src/components/SankeyChart/SankeyChart.test.tsx
@@ -91,6 +91,17 @@ const dataWithoutColors: () => IChartProps = () => ({
   },
 });
 
+const dataWithPrototypeNodeId: () => IChartProps = () => ({
+  chartTitle: 'Sankey Chart',
+  SankeyChartData: {
+    nodes: [
+      { nodeId: '__proto__', name: 'Source' },
+      { nodeId: 'target', name: 'Target' },
+    ],
+    links: [{ source: 0, target: 1, value: 10 }],
+  },
+});
+
 describe('Sankey Chart snapShot testing', () => {
   beforeEach(sharedBeforeEach);
   afterEach(sharedAfterEach);
@@ -143,6 +154,13 @@ describe('Sankey Chart snapShot testing', () => {
     expect(container).toMatchSnapshot();
   });
 
+  it('renders Sankey correctly with a prototype property node ID', () => {
+    const { getByText } = render(<SankeyChart data={dataWithPrototypeNodeId()} height={500} width={800} />);
+
+    expect(getByText('Source')).toBeDefined();
+    expect(getByText('Target')).toBeDefined();
+  });
+
   describe.skip('number formatting', () => {
     it('renders Sankey correctly by formatting large numbers', () => {
       // ARRANGE
diff --git a/packages/charts/react-charts/library/src/components/SankeyChart/SankeyChart.test.tsx b/packages/charts/react-charts/library/src/components/SankeyChart/SankeyChart.test.tsx
index 429819483414b..baf9a6c553884 100644
--- a/packages/charts/react-charts/library/src/components/SankeyChart/SankeyChart.test.tsx
+++ b/packages/charts/react-charts/library/src/components/SankeyChart/SankeyChart.test.tsx
@@ -99,6 +99,19 @@ function chartPointsWithStringNodeId(): ChartProps {
   };
 }
 
+function chartPointsWithPrototypeNodeId(): ChartProps {
+  return {
+    chartTitle: 'Sankey Chart',
+    SankeyChartData: {
+      nodes: [
+        { nodeId: '__proto__', name: 'Source' },
+        { nodeId: 'target', name: 'Target' },
+      ],
+      links: [{ source: 0, target: 1, value: 10 }],
+    },
+  };
+}
+
 const emptyChartPoints: ChartProps = {
   chartData: [],
 };
@@ -603,3 +616,17 @@ describe('SankeyChart - Min Height of Node Test', () => {
     expect(component).toMatchSnapshot();
   });
 });
+
+describe('Sankey chart prototype property node IDs', () => {
+  beforeEach(sharedBeforeEach);
+
+  testWithoutWait(
+    'Should render the Sankey chart with a prototype property node ID',
+    SankeyChart,
+    { data: chartPointsWithPrototypeNodeId() },
+    () => {
+      expect(screen.getByText('Source')).toBeDefined();
+      expect(screen.getByText('Target')).toBeDefined();
+    },
+  );
+});
diff --git a/packages/charts/react-charts/library/src/components/SankeyChart/SankeyChart.tsx b/packages/charts/react-charts/library/src/components/SankeyChart/SankeyChart.tsx
index fa5dbba5ef5f5..69feafc5e42b7 100644
--- a/packages/charts/react-charts/library/src/components/SankeyChart/SankeyChart.tsx
+++ b/packages/charts/react-charts/library/src/components/SankeyChart/SankeyChart.tsx
@@ -28,7 +28,7 @@ type NodeValues = ItemValues<number>;
 type LinkItemValues<T> = { [key: NodeId]: ItemValues<T> };
 type LinkValues = LinkItemValues<number>;
 
-type NodesInColumns = { [key: number]: SNode[] };
+type NodesInColumns = ItemValues<SNode[]>;
 type NormalizedData = SankeyChartData & {
   width: number;
   height: number;
@@ -37,6 +37,10 @@ type NormalizedData = SankeyChartData & {
 type NodeColors = { fillColor: string; borderColor: string };
 type SankeyLayoutGenerator = SankeyLayout<SankeyGraph<{}, {}>, {}, {}>;
 
+function createNodeIdMap<T>(): ItemValues<T> {
+  return Object.setPrototypeOf({}, null);
+}
+
 const NON_SELECTED_NODE_AND_STREAM_COLOR: string = '#757575';
 const DEFAULT_NODE_COLORS: NodeColors[] = [
   { fillColor: '#00758F', borderColor: '#002E39' },
@@ -162,7 +166,7 @@ function getSelectedLinksforStreamHover(singleLink: SLink): {
  */
 // This is exported for unit tests.
 export function groupNodesByColumn(graph: SankeyChartData): NodesInColumns {
-  const nodesInColumn: NodesInColumns = {};
+  const nodesInColumn = createNodeIdMap<SNode[]>();
   graph.nodes.forEach((node: SNode) => {
     const columnId = node.layer!;
     if (nodesInColumn[columnId]) {
@@ -299,7 +303,7 @@ function duplicateData(data: SankeyChartData): SankeyChartData {
 }
 
 function valuesOfNodes(nodes: SNode[]): NodeValues {
-  const result: NodeValues = {};
+  const result = createNodeIdMap<number>();
   nodes.forEach((node: SNode) => {
     result[node.nodeId as NodeId] = node.value!;
   });
@@ -307,12 +311,12 @@ function valuesOfNodes(nodes: SNode[]): NodeValues {
 }
 
 function valuesOfLinks(links: SLink[]): LinkValues {
-  const result: LinkValues = {};
+  const result = createNodeIdMap<ItemValues<number>>();
   links.forEach((link: SLink) => {
     const sourceId = idFromNumberOrSNode(link.source);
     let sourceToTarget = result[sourceId];
     if (!sourceToTarget) {
-      sourceToTarget = {};
+      sourceToTarget = createNodeIdMap<number>();
       result[sourceId] = sourceToTarget;
     }
     sourceToTarget[idFromNumberOrSNode(link.target)] = link.value;
@@ -464,12 +468,12 @@ function computeLinkAttributes(
   linkAriaLabel: (link: SLink) => string,
   linkId: string,
 ): LinkItemValues<RenderedLinkAttributes> {
-  const result: LinkItemValues<RenderedLinkAttributes> = {};
+  const result = createNodeIdMap<ItemValues<RenderedLinkAttributes>>();
   links.forEach((link: SLink, index: number) => {
     const sourceId = idFromNumberOrSNode(link.source);
     let sourceToTarget = result[sourceId];
     if (!sourceToTarget) {
-      sourceToTarget = {};
+      sourceToTarget = createNodeIdMap<RenderedLinkAttributes>();
       result[sourceId] = sourceToTarget;
     }
     sourceToTarget[idFromNumberOrSNode(link.target)] = {
@@ -618,7 +622,7 @@ export const SankeyChart: React.FunctionComponent<SankeyChartProps> = React.forw
 
   const _computeNodeAttributes = React.useCallback(
     (nodes: SNode[], nodeAriaLabel: (node: SNode, weight: number) => string): ItemValues<RenderedNodeAttributes> => {
-      const result: ItemValues<RenderedNodeAttributes> = {};
+      const result = createNodeIdMap<RenderedNodeAttributes>();
       const weightSpan = select('.nodeName').append('text').attr('class', 'tempText').append('tspan').text(null);
       const nameSpan = select('.nodeName')
         .append('text')