diff --git a/packages/utils/src/shorthand-time.ts b/packages/utils/src/shorthand-time.ts
index 94f5c54f..30964d6d 100644
--- a/packages/utils/src/shorthand-time.ts
+++ b/packages/utils/src/shorthand-time.ts
@@ -28,8 +28,11 @@ export const shorthandToMilliseconds = (
 
 		// Check if the string is purely numeric
 		if (Number.isNaN(Number(shorthand))) {
-			// Use a case-insensitive regex that supports decimals and 'ms' unit
-			const match = /^([\d.]+)\s*(ms|s|m|h|hr|d)$/i.exec(shorthand);
+			// Require at least one digit and at most one decimal point.
+			// Keep the decimal part in one group to prevent excess backtracking.
+			const match = /^(\d+(?:\.\d*)?|\.\d+)\s*(ms|s|m|h|hr|d)$/i.exec(
+				shorthand,
+			);
 
 			if (!match) {
 				throw new Error(
diff --git a/packages/utils/test/shorthand-time.test.ts b/packages/utils/test/shorthand-time.test.ts
index c043096a..10d38fb9 100644
--- a/packages/utils/test/shorthand-time.test.ts
+++ b/packages/utils/test/shorthand-time.test.ts
@@ -34,6 +34,20 @@ describe("time parser", () => {
 			"Unsupported time format: \"1z\". Use 'ms', 's', 'm', 'h', 'hr', or 'd'.",
 		);
 	});
+	test.each(["1.2.3s", "1..5s", "..s", ".s", ".m"])(
+		'reject a malformed number in "%s"',
+		(value) => {
+			expect(() => shorthandToMilliseconds(value)).toThrowError(
+				`Unsupported time format: "${value}"`,
+			);
+		},
+	);
+	test.each([
+		[".5s", 500],
+		["5.s", 5000],
+	])('convert "%s" to milliseconds', (value, expected) => {
+		expect(shorthandToMilliseconds(value)).toBe(expected);
+	});
 	test("send in string with number", () => {
 		expect(shorthandToMilliseconds("1000")).toBe(1000);
 	});