CVE-2025-48174: Aomedia Libavif Buffer Overflow Flaw

CVE-2025-48174 Overview

CVE-2025-48174 is an integer overflow vulnerability in the makeRoom function within stream.c of the libavif library. When processing AVIF image files, the stream->offset + size calculation can overflow, leading to a resultant buffer overflow condition. This vulnerability affects libavif versions prior to 1.3.0 and can be exploited remotely via specially crafted AVIF image files.

Critical Impact
Successful exploitation of this integer overflow vulnerability can lead to high-impact integrity and availability compromise, potentially enabling attackers to corrupt memory, crash applications, or achieve further exploitation through heap manipulation.

Affected Products

aomedia libavif versions prior to 1.3.0

Discovery Timeline

2025-05-16 - CVE-2025-48174 published to NVD
2025-11-03 - Last updated in NVD database

Technical Details for CVE-2025-48174

Vulnerability Analysis

The vulnerability exists in the makeRoom function within src/stream.c of the libavif library. This function is responsible for ensuring sufficient buffer space is available when writing to a raw stream during AVIF image processing. The core issue stems from an arithmetic operation that calculates the required buffer size by adding stream->offset and size together.

When both values are sufficiently large, their sum can exceed the maximum representable value for the size_t type, causing the result to wrap around to a small value. This integer overflow leads to an undersized buffer allocation, and subsequent write operations overflow the allocated buffer, corrupting adjacent heap memory.

The vulnerability is classified as CWE-190 (Integer Overflow or Wraparound). Attackers can exploit this by crafting malicious AVIF image files with specific metadata or chunk sizes designed to trigger the overflow condition when the image is decoded by an application using the vulnerable libavif library.

Root Cause

The root cause is an insufficient integer overflow check in the makeRoom function. The original code calculated neededSize = stream->offset + size before performing any overflow validation, meaning the overflow had already occurred by the time the check was evaluated. This flawed check compared neededSize < stream->offset after the potentially overflowed calculation, which is an unreliable method for detecting integer overflow.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker can deliver a maliciously crafted AVIF image file through various channels such as:

Web browsers rendering AVIF images
Image processing applications and libraries
Content management systems handling image uploads
Email clients with image preview functionality

When the target application parses the malicious AVIF file, the integer overflow triggers in the makeRoom function, leading to heap buffer overflow and potential memory corruption.

// Security patch showing the integer overflow fix
// Source: https://github.com/AOMediaCodec/libavif/commit/50a743062938a3828581d725facc9c2b92a1d109

 #define AVIF_STREAM_BUFFER_INCREMENT (1024 * 1024)
 static avifResult makeRoom(avifRWStream * stream, size_t size)
 {
-    size_t neededSize = stream->offset + size;
-    if (neededSize < stream->offset) {
-        return AVIF_RESULT_INVALID_ARGUMENT;
+    if (size > SIZE_MAX - stream->offset) {
+        return AVIF_RESULT_OUT_OF_MEMORY;
     }
+    size_t neededSize = stream->offset + size;
     size_t newSize = stream->raw->size;
     while (newSize < neededSize) {
         newSize += AVIF_STREAM_BUFFER_INCREMENT;

Detection Methods for CVE-2025-48174

Indicators of Compromise

Unexpected application crashes or segmentation faults when processing AVIF image files
Memory corruption errors or heap corruption warnings from memory sanitizers
Abnormal memory allocation patterns in applications using libavif
Core dumps indicating heap overflow in stream-related functions

Detection Strategies

Deploy memory sanitizers (AddressSanitizer, MemorySanitizer) in development and testing environments to detect heap overflows
Monitor application logs for AVIF decoding failures with out-of-memory or invalid argument errors
Implement file integrity monitoring for applications that process untrusted AVIF images
Use fuzzing tools to test AVIF processing pipelines for memory safety issues

Monitoring Recommendations

Enable crash reporting and stack trace collection for applications processing AVIF images
Monitor system memory usage patterns for anomalies during image processing workflows
Implement network traffic analysis to detect delivery of suspiciously large or malformed AVIF files
Configure endpoint detection to alert on heap corruption signatures in processes using libavif

How to Mitigate CVE-2025-48174

Immediate Actions Required

Update libavif to version 1.3.0 or later immediately
Audit all applications and dependencies that utilize libavif for AVIF image processing
Consider temporarily disabling AVIF image support if updates cannot be applied immediately
Implement input validation to reject abnormally large AVIF files at ingestion points

Patch Information

The vulnerability has been addressed through multiple commits to the libavif repository. The fix changes the overflow check to validate before the addition operation occurs, using the safe pattern if (size > SIZE_MAX - stream->offset) which prevents the overflow from happening in the first place. Organizations should update to libavif version 1.3.0 or apply the patches from the following resources:

Debian users should refer to the Debian LTS Security Announcement for distribution-specific updates.

Workarounds

Restrict AVIF image processing to trusted sources only until patches can be applied
Implement Content Security Policy headers to limit AVIF image loading from untrusted origins
Deploy web application firewalls with rules to inspect and filter malformed AVIF content
Use containerization or sandboxing for image processing services to limit blast radius

bash

# Example: Check installed libavif version and update on Debian-based systems
dpkg -l | grep libavif
sudo apt update && sudo apt upgrade libavif-dev libavif15
# Verify patched version (1.3.0 or later)
pkg-config --modversion libavif