diff --git a/apps/desktop/src/renderer/src/stores/tab-store.ts b/apps/desktop/src/renderer/src/stores/tab-store.ts
index c32609d67..fcf805f79 100644
--- a/apps/desktop/src/renderer/src/stores/tab-store.ts
+++ b/apps/desktop/src/renderer/src/stores/tab-store.ts
@@ -2,6 +2,7 @@ import { create } from "zustand";
 import { createJSONStorage, persist } from "zustand/middleware";
 import { arrayMove } from "@dnd-kit/sortable";
 import { createPersistStorage, defaultStorage } from "@multica/core/platform";
+import { createSafeId } from "@multica/core/utils";
 import type { DataRouter } from "react-router-dom";
 import { createTabRouter } from "../routes";
 
@@ -69,7 +70,7 @@ export function resolveRouteIcon(pathname: string): string {
 const DEFAULT_PATH = "/issues";
 
 function createId(): string {
-  return crypto.randomUUID();
+  return createSafeId();
 }
 
 function makeTab(path: string, title: string, icon: string): Tab {
diff --git a/packages/core/api/client.ts b/packages/core/api/client.ts
index 26b3ae504..30f348e3a 100644
--- a/packages/core/api/client.ts
+++ b/packages/core/api/client.ts
@@ -52,6 +52,7 @@ import type {
   ReorderPinsRequest,
 } from "../types";
 import { type Logger, noopLogger } from "../logger";
+import { createRequestId } from "../utils";
 
 export interface ApiClientOptions {
   logger?: Logger;
@@ -108,7 +109,7 @@ export class ApiClient {
   }
 
   private async fetch<T>(path: string, init?: RequestInit): Promise<T> {
-    const rid = crypto.randomUUID().slice(0, 8);
+    const rid = createRequestId();
     const start = Date.now();
     const method = init?.method ?? "GET";
 
@@ -610,7 +611,7 @@ export class ApiClient {
     if (opts?.issueId) formData.append("issue_id", opts.issueId);
     if (opts?.commentId) formData.append("comment_id", opts.commentId);
 
-    const rid = crypto.randomUUID().slice(0, 8);
+    const rid = createRequestId();
     const start = Date.now();
     this.logger.info("→ POST /api/upload-file", { rid });
 
diff --git a/packages/core/utils.test.ts b/packages/core/utils.test.ts
new file mode 100644
index 000000000..e409b1d6f
--- /dev/null
+++ b/packages/core/utils.test.ts
@@ -0,0 +1,33 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { createRequestId, createSafeId, generateUUID } from "./utils";
+
+afterEach(() => {
+  vi.unstubAllGlobals();
+  vi.restoreAllMocks();
+});
+
+describe("utils id helpers", () => {
+  it("generateUUID returns a valid UUID v4", () => {
+    const id = generateUUID();
+    expect(id).toMatch(/^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i);
+  });
+
+  it("createSafeId falls back when crypto.randomUUID is unavailable", () => {
+    vi.stubGlobal("crypto", {
+      getRandomValues: (arr: Uint8Array) => {
+        for (let i = 0; i < arr.length; i++) arr[i] = i;
+        return arr;
+      },
+    });
+
+    const id = createSafeId();
+    expect(id).toMatch(/^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i);
+  });
+
+  it("createRequestId defaults to length 8 and respects custom length", () => {
+    vi.spyOn(globalThis.crypto, "randomUUID").mockReturnValue("12345678-1234-4abc-8def-1234567890ab");
+
+    expect(createRequestId()).toBe("12345678");
+    expect(createRequestId(12)).toBe("123456781234");
+  });
+});
diff --git a/packages/core/utils.ts b/packages/core/utils.ts
index 096f0f5d5..072812c0d 100644
--- a/packages/core/utils.ts
+++ b/packages/core/utils.ts
@@ -8,3 +8,43 @@ export function timeAgo(dateStr: string): string {
   const days = Math.floor(hours / 24);
   return `${days}d ago`;
 }
+
+export function generateUUID(): string {
+  const cryptoObj = globalThis.crypto;
+
+  if (!cryptoObj?.getRandomValues) {
+    throw new Error("Secure UUID generation requires crypto.getRandomValues");
+  }
+
+  const bytes = new Uint8Array(16);
+  cryptoObj.getRandomValues(bytes);
+
+  bytes[6] = ((bytes[6] ?? 0) & 0x0f) | 0x40; // version 4
+  bytes[8] = ((bytes[8] ?? 0) & 0x3f) | 0x80; // variant 1
+
+  const hex = Array.from(bytes, (b) => b.toString(16).padStart(2, "0")).join("");
+
+  return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20)}`;
+}
+
+/**
+ * Generate an id that prefers crypto.randomUUID but falls back in non-secure contexts.
+ */
+export function createSafeId(): string {
+  const cryptoObj = globalThis.crypto;
+
+  if (cryptoObj?.randomUUID) {
+    try {
+      return cryptoObj.randomUUID();
+    } catch {
+      // Fall through to fallback.
+    }
+  }
+
+  return generateUUID();
+}
+
+/** Request id helper used for logs/tracing headers. */
+export function createRequestId(length = 8): string {
+  return createSafeId().replace(/-/g, "").slice(0, length);
+}
diff --git a/packages/views/editor/extensions/file-upload.ts b/packages/views/editor/extensions/file-upload.ts
index 9f89cbda3..d2874a62b 100644
--- a/packages/views/editor/extensions/file-upload.ts
+++ b/packages/views/editor/extensions/file-upload.ts
@@ -1,6 +1,7 @@
 import { Extension } from "@tiptap/core";
 import { Plugin, PluginKey } from "@tiptap/pm/state";
 import type { UploadResult } from "@multica/core/hooks/use-file-upload";
+import { createSafeId } from "@multica/core/utils";
 
 /** Find and remove a fileCard node by uploadId. */
  
@@ -109,7 +110,7 @@ export async function uploadAndInsertFile(
     }
   } else {
     // Non-image: insert skeleton fileCard → upload → finalize with real URL
-    const uploadId = crypto.randomUUID();
+    const uploadId = createSafeId();
     const cardAttrs = { filename: file.name, href: "", fileSize: file.size, uploading: true, uploadId };
     const insertContent = { type: "fileCard", attrs: cardAttrs };
     if (pos !== undefined) {