CVE-2025-14369: dr_flac Audio Decoder DoS Vulnerability

CVE-2025-14369 Overview

CVE-2025-14369 is an integer overflow vulnerability in dr_flac, an audio decoder within the dr_libs toolset. The vulnerability exists because the decoder trusts the totalPCMFrameCount field from FLAC metadata without proper validation before calculating buffer size. An attacker can exploit this flaw by crafting a malicious FLAC file that, when processed by an application using dr_flac, triggers a denial of service condition.

Critical Impact

Applications using the dr_flac library for audio processing are vulnerable to denial of service attacks when processing maliciously crafted FLAC files. This could affect media players, audio converters, game engines, and any other software utilizing the dr_libs audio decoding libraries.

Affected Products

• dr_flac (part of dr_libs audio decoding library)
• Applications and software utilizing dr_libs for FLAC audio decoding
• Game engines and media applications incorporating dr_flac

Discovery Timeline

• 2026-01-20 - CVE-2025-14369 published to NVD
• 2026-01-20 - Last updated in NVD database

Technical Details for CVE-2025-14369

Vulnerability Analysis

This vulnerability is classified as an integer overflow that occurs during buffer size calculation in the dr_flac audio decoder. The decoder reads the totalPCMFrameCount field directly from FLAC file metadata and uses this value in arithmetic operations to determine the required buffer size for audio data processing. When a specially crafted FLAC file contains a manipulated totalPCMFrameCount value, the multiplication or addition operations used to calculate the buffer size can overflow, resulting in allocation of an incorrectly sized buffer.

The local attack vector requires user interaction—specifically, the victim must open or process a malicious FLAC file. While no confidentiality or integrity impact exists, the availability impact is significant as exploitation leads to application crashes or hangs.

Root Cause

The root cause of CVE-2025-14369 lies in the dr_flac library's implicit trust of metadata values read from FLAC files without adequate bounds checking. The totalPCMFrameCount field, which indicates the total number of audio frames in the stream, is used directly in buffer size calculations. When this value is maliciously set to an extremely large number, subsequent arithmetic operations overflow, causing the calculated buffer size to wrap around to a much smaller value than intended. This leads to heap buffer underallocation and subsequent memory corruption when audio data is written to the undersized buffer.

Attack Vector

The attack requires local access where an attacker delivers a specially crafted FLAC file to the victim. The victim must then open or process this file using an application that incorporates the vulnerable dr_flac library. The exploitation flow involves:

1. Attacker crafts a FLAC file with a manipulated totalPCMFrameCount metadata field set to a value that will cause integer overflow when multiplied by the bytes-per-sample or channel count
2. When the application parses the FLAC metadata, it reads the malicious value without validation
3. Buffer size calculation overflows, resulting in undersized memory allocation
4. Application crashes when attempting to process audio data into the insufficient buffer

For technical details on the vulnerability mechanism and fix, refer to the GitHub Commit Update and the CERT Vulnerability Advisory.

Detection Methods for CVE-2025-14369

Indicators of Compromise

• Application crashes occurring specifically when processing FLAC audio files
• Abnormal memory allocation patterns when handling FLAC file metadata
• Error logs indicating buffer allocation failures or memory access violations during audio decoding operations

Detection Strategies

• Monitor application crash dumps for stack traces involving dr_flac decoding functions
• Implement file integrity monitoring to detect suspicious FLAC files with anomalous metadata values
• Deploy endpoint detection rules to identify applications crashing after opening audio files from untrusted sources

Monitoring Recommendations

• Enable detailed logging for applications utilizing dr_libs audio decoding functionality
• Configure application crash reporting to capture and analyze failures in audio processing components
• Implement file scanning policies for incoming FLAC files, particularly from external or untrusted sources

How to Mitigate CVE-2025-14369

Immediate Actions Required

• Update the dr_libs library to the patched version containing the fix for this vulnerability
• Restrict processing of FLAC files from untrusted or unknown sources
• Implement input validation at the application level to reject FLAC files with suspicious metadata values

Patch Information

The vulnerability has been addressed in a commit to the dr_libs repository. The fix adds proper bounds checking for the totalPCMFrameCount field before using it in buffer size calculations, preventing integer overflow conditions. Organizations should update to the latest version of dr_libs that includes commit b2197b2eb7bb609df76315bebf44db4ec2a1aed0. For detailed patch information, see the GitHub Commit Update.

Workarounds

• Disable FLAC file processing in applications where this functionality is not essential
• Implement application-level sandboxing to contain potential crashes from malicious audio files
• Use alternative FLAC decoding libraries that include proper integer overflow protections until dr_libs can be updated
• Configure endpoint protection to block execution of applications processing FLAC files from untrusted sources

To verify your dr_libs version and check for the presence of the security fix, review the source code or commit history of your library installation against the patched commit referenced in the security advisory.