diff --git a/lib/tdf3/src/utils/zip-reader.ts b/lib/tdf3/src/utils/zip-reader.ts
index 585129ee..e76dff48 100644
--- a/lib/tdf3/src/utils/zip-reader.ts
+++ b/lib/tdf3/src/utils/zip-reader.ts
@@ -8,6 +8,8 @@ const CD_SIGNATURE = 0x02014b50;
 const CENTRAL_DIRECTORY_RECORD_FIXED_SIZE = 46;
 const LOCAL_FILE_HEADER_FIXED_SIZE = 30;
 const VERSION_NEEDED_TO_EXTRACT_ZIP64 = 45;
+const manifestMaxSize = 1024 * 1024 * 10; // 10 MB
+
 const cp437 =
   '\u0000☺☻♥♦♣♠•◘○◙♂♀♪♫☼►◄↕‼¶§▬↨↑↓→←∟↔▲▼ !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~⌂ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜ¢£¥₧ƒáíóúñѪº¿⌐¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ ';
 
@@ -92,6 +94,11 @@ export class ZipReader {
       throw new Error('Unable to retrieve CD manifest');
     }
     const byteStart = cdObj.relativeOffsetOfLocalHeader + cdObj.headerLength;
+    if (cdObj.uncompressedSize > manifestMaxSize) {
+      throw new Error(
+        `manifest file too large: ${(cdObj.uncompressedSize >> 10).toLocaleString()} KiB`
+      );
+    }
     const byteEnd = byteStart + cdObj.uncompressedSize;
     const manifest = await this.getChunk(byteStart, byteEnd);
 
diff --git a/lib/tests/mocha/unit/zip.spec.ts b/lib/tests/mocha/unit/zip.spec.ts
index 4b384795..a5386a27 100644
--- a/lib/tests/mocha/unit/zip.spec.ts
+++ b/lib/tests/mocha/unit/zip.spec.ts
@@ -1,7 +1,12 @@
 import { expect } from 'chai';
 
 import { encodeArrayBuffer } from '../../../src/encodings/base64.js';
-import { parseCDBuffer, readUInt64LE } from '../../../tdf3/src/utils/zip-reader.js';
+import {
+  CentralDirectory,
+  parseCDBuffer,
+  readUInt64LE,
+  ZipReader,
+} from '../../../tdf3/src/utils/zip-reader.js';
 import { ZipWriter, dateToDosDateTime, writeUInt64LE } from '../../../tdf3/src/utils/zip-writer.js';
 
 describe('zip utilities', () => {
@@ -170,3 +175,27 @@ describe('zip utilities', () => {
     });
   });
 });
+
+describe('reader', () => {
+  it('fails on bad manifest size', async () => {
+    const reader = new ZipReader(async () => new Uint8Array([]));
+    const fileName = '0.manifest.json';
+    try {
+      expect(
+        await reader.getManifest(
+          [
+            {
+              fileName,
+              relativeOffsetOfLocalHeader: 0,
+              headerLength: 1024,
+              uncompressedSize: 1024 * 1024 * 128,
+            } as CentralDirectory,
+          ],
+          fileName
+        )
+      ).to.be.undefined;
+    } catch (e) {
+      expect(e.message).to.contain('too large');
+    }
+  });
+});