diff --git a/‎lib/eslint/eslint.js‎
Lines changed: 29 additions & 6 deletions b/‎lib/eslint/eslint.js‎
Lines changed: 29 additions & 6 deletions
diff --git a/‎tests/lib/eslint/eslint.js‎
Lines changed: 74 additions & 0 deletions b/‎tests/lib/eslint/eslint.js‎
Lines changed: 74 additions & 0 deletions
@@ -107,6 +107,34 @@ function createRulesMeta(rules) {
 	}, {});
 }
 
+/**
+ * Gets the replacement rule names from a deprecated rule's metadata.
+ * @param {RulesMeta} meta The rule metadata.
+ * @returns {string[]} Replacement rule names.
+ */
+function getDeprecatedRuleReplacements(meta) {
+	if (typeof meta.deprecated !== "object") {
+		return meta.replacedBy || [];
+	}
+
+	const { replacedBy } = meta.deprecated;
+
+	if (!Array.isArray(replacedBy)) {
+		return [];
+	}
+
+	return replacedBy.map(replacement => {
+		if (typeof replacement !== "object" || replacement === null) {
+			return "";
+		}
+
+		const pluginName = replacement.plugin?.name;
+		const ruleName = replacement.rule?.name;
+
+		return `${typeof pluginName === "string" ? `${getShorthandName(pluginName, "eslint-plugin")}/` : ""}${typeof ruleName === "string" ? ruleName : ""}`;
+	});
+}
+
 /** @type {WeakMap<CalculatedConfig, DeprecatedRuleInfo[]>} */
 const usedDeprecatedRulesCache = new WeakMap();
 
@@ -144,12 +172,7 @@ function getOrFindUsedDeprecatedRules(eslint, maybeFilePath) {
 
 					retv.push({
 						ruleId,
-						replacedBy: usesNewFormat
-							? (meta.deprecated.replacedBy?.map(
-									replacement =>
-										`${replacement.plugin?.name !== void 0 ? `${getShorthandName(replacement.plugin.name, "eslint-plugin")}/` : ""}${replacement.rule?.name ?? ""}`,
-								) ?? [])
-							: meta.replacedBy || [],
+						replacedBy: getDeprecatedRuleReplacements(meta),
 						info: usesNewFormat ? meta.deprecated : void 0,
 					});
 				}
 
@@ -4354,6 +4354,80 @@ describe("ESLint", () => {
 					},
 				]);
 			});
+
+			it("should ignore replacement metadata that is not an array", async () => {
+				const deprecated = {
+					replacedBy: "replacement",
+				};
+
+				eslint = new ESLint({
+					cwd: originalDir,
+					overrideConfigFile: true,
+					overrideConfig: {
+						plugins: {
+							test: {
+								rules: {
+									deprecated: {
+										meta: { deprecated },
+										create: () => ({}),
+									},
+								},
+							},
+						},
+						rules: {
+							"test/deprecated": "error",
+						},
+					},
+				});
+				const results = await eslint.lintFiles(["lib/cli*.js"]);
+
+				assert.deepStrictEqual(results[0].usedDeprecatedRules, [
+					{
+						ruleId: "test/deprecated",
+						replacedBy: [],
+						info: deprecated,
+					},
+				]);
+			});
+
+			it("should handle invalid replacement metadata entries", async () => {
+				const deprecated = {
+					replacedBy: [
+						null,
+						{ plugin: { name: null } },
+						{ plugin: { name: null }, rule: { name: "name" } },
+					],
+				};
+
+				eslint = new ESLint({
+					cwd: originalDir,
+					overrideConfigFile: true,
+					overrideConfig: {
+						plugins: {
+							test: {
+								rules: {
+									deprecated: {
+										meta: { deprecated },
+										create: () => ({}),
+									},
+								},
+							},
+						},
+						rules: {
+							"test/deprecated": "error",
+						},
+					},
+				});
+				const results = await eslint.lintFiles(["lib/cli*.js"]);
+
+				assert.deepStrictEqual(results[0].usedDeprecatedRules, [
+					{
+						ruleId: "test/deprecated",
+						replacedBy: ["", "", "name"],
+						info: deprecated,
+					},
+				]);
+			});
 		});
 
 		// working