diff --git a/web/ui/module/codemirror-promql/src/complete/hybrid.test.ts b/web/ui/module/codemirror-promql/src/complete/hybrid.test.ts
index cc73161dce..e958a8113b 100644
--- a/web/ui/module/codemirror-promql/src/complete/hybrid.test.ts
+++ b/web/ui/module/codemirror-promql/src/complete/hybrid.test.ts
@@ -652,11 +652,22 @@ describe('durationWithUnitRegexp test', () => {
       { input: '2d', expected: true },
       { input: '1w', expected: true },
       { input: '1y', expected: true },
+      { input: '1d2h', expected: true },
+      { input: '2h30m', expected: true },
+      { input: '1h2m3s', expected: true },
+      { input: '250ms2s', expected: true },
+      { input: '2h3m4s5ms', expected: true },
+      { input: '5', expected: false },
+      { input: '5m5', expected: false },
+      { input: 'm', expected: false },
+      { input: 'd', expected: false },
+      { input: '', expected: false },
+      { input: '1hms', expected: false },
+      { input: '2x', expected: false },
     ];
-
     testCases.forEach(({ input, expected }) => {
       expect(durationWithUnitRegexp.test(input)).toBe(expected);
-    });
+    });        
   });
 
   it('should not match durations without units or partial units', () => {
diff --git a/web/ui/module/codemirror-promql/src/complete/hybrid.ts b/web/ui/module/codemirror-promql/src/complete/hybrid.ts
index 8a2d575552..36fb59be5b 100644
--- a/web/ui/module/codemirror-promql/src/complete/hybrid.ts
+++ b/web/ui/module/codemirror-promql/src/complete/hybrid.ts
@@ -166,13 +166,25 @@ function arrayToCompletionResult(data: Completion[], from: number, to: number, i
   } as CompletionResult;
 }
 
-// Matches complete duration with units (e.g., 5m, 30s, 1h, 500ms)
-export const durationWithUnitRegexp = new RegExp(`^\\d+(?:${durationTerms.map((term) => escapeRegExp(term.label)).join('|')})$`);
-
-function escapeRegExp(value: string): string {
-  return value.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+// Polyfill RegExp.escape for compatibility with ES2024 and TypeScript.
+// Ensures safe, standards-based regex escaping in all environments.
+declare global {
+  interface RegExpConstructor {
+    escape?: (s: string) => string;
+  }
 }
 
+if (!RegExp.escape) {
+  RegExp.escape = function(s: string): string {
+    return s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+  };
+}
+
+// Matches complete PromQL durations, including compound units (e.g., 5m, 1d2h, 1h30m, etc.)
+export const durationWithUnitRegexp = new RegExp(
+  `^(\\d+(${durationTerms.map(term => RegExp.escape!(term.label)).join('|')}))+$`
+);
+
 // Determines if a duration already has a complete time unit to prevent autocomplete insertion (issue #15452)
 function hasCompleteDurationUnit(state: EditorState, node: SyntaxNode): boolean {
   if (node.from >= node.to) {