CVE-2025-70304: GPAC Buffer Overflow Vulnerability

CVE-2025-70304 Overview

A buffer overflow vulnerability exists in the vobsub_get_subpic_duration() function of GPAC v2.4.0, an open-source multimedia framework used for processing, packaging, and streaming multimedia content. This stack-based buffer overflow (CWE-121) allows remote attackers to cause a Denial of Service (DoS) condition by sending specially crafted packets to the vulnerable component.

GPAC is widely used in multimedia applications for MP4 file manipulation, DASH streaming, and subtitle processing. The vulnerable function handles VobSub subtitle duration parsing, which is commonly used for DVD-style subtitles in multimedia containers.

Critical Impact

Remote attackers can crash GPAC applications by exploiting this buffer overflow through crafted network packets, causing service disruption without requiring authentication or user interaction.

Affected Products

• GPAC v2.4.0
• Applications and services utilizing GPAC v2.4.0 for multimedia processing
• Systems processing VobSub subtitle streams through GPAC

Discovery Timeline

• 2026-01-15 - CVE CVE-2025-70304 published to NVD
• 2026-01-16 - Last updated in NVD database

Technical Details for CVE-2025-70304

Vulnerability Analysis

This vulnerability is classified as CWE-121: Stack-based Buffer Overflow. The flaw exists within the vobsub_get_subpic_duration() function, which processes VobSub subtitle picture duration data. When parsing malformed or oversized input data, the function fails to properly validate buffer boundaries before writing data to a stack-allocated buffer.

The vulnerability can be exploited remotely over the network without requiring any privileges or user interaction. While the attack does not compromise confidentiality or integrity, successful exploitation results in complete denial of service by crashing the application processing the malicious input.

Root Cause

The root cause is improper bounds checking in the vobsub_get_subpic_duration() function when processing subtitle duration data. The function allocates a fixed-size buffer on the stack and copies input data without verifying that the source data length does not exceed the allocated buffer size. When an attacker provides oversized or malformed input, the function writes beyond the buffer boundaries, corrupting adjacent stack memory and causing the application to crash.

Attack Vector

The attack vector is network-based, requiring an attacker to send a crafted packet containing malicious VobSub subtitle data to a GPAC application. The attack has low complexity and requires:

1. A target system running GPAC v2.4.0 or an application using the vulnerable GPAC library
2. Network connectivity to deliver the malicious payload
3. A crafted packet that triggers the buffer overflow in vobsub_get_subpic_duration()

The exploitation mechanism involves crafting subtitle data with oversized fields that exceed the expected buffer limits. When the vulnerable function attempts to process this data, it overflows the stack buffer, leading to memory corruption and application termination. Technical details and proof-of-concept information are available in the GitHub PoC Repository.

Detection Methods for CVE-2025-70304

Indicators of Compromise

• Unexpected crashes or segmentation faults in GPAC processes or applications using GPAC libraries
• Core dumps indicating stack corruption in processes handling multimedia content
• Abnormal network traffic patterns containing malformed VobSub subtitle data
• Repeated service restarts for multimedia processing applications

Detection Strategies

• Monitor application logs for crash events related to GPAC processes or vobsub_get_subpic_duration() function calls
• Implement network intrusion detection rules to identify malformed VobSub subtitle packets
• Deploy endpoint detection to alert on repeated crashes of GPAC-based applications
• Use application sandboxing to contain potential exploitation attempts

Monitoring Recommendations

• Enable crash reporting and analysis for systems running GPAC v2.4.0
• Monitor system stability metrics for multimedia processing services
• Implement alerting for unusual patterns of service restarts or application failures
• Review network traffic logs for suspicious multimedia content delivery

How to Mitigate CVE-2025-70304

Immediate Actions Required

• Identify all systems running GPAC v2.4.0 or applications utilizing the vulnerable GPAC library
• Restrict network access to GPAC-based services where possible
• Implement input validation for multimedia content before processing with GPAC
• Consider disabling VobSub subtitle processing if not required for business operations

Patch Information

At the time of publication, users should monitor the official GPAC project for security updates addressing this vulnerability. Check the GitHub PoC Repository for the latest information regarding this issue and track GPAC releases for patched versions.

Workarounds

• Implement network segmentation to limit exposure of GPAC-based services
• Use a Web Application Firewall (WAF) or network filtering to block malformed multimedia packets
• Process untrusted multimedia content in isolated sandbox environments
• Disable VobSub subtitle processing in GPAC configuration if this functionality is not required

# Example: Restrict network access to GPAC services
# Limit incoming connections to trusted sources only
iptables -A INPUT -p tcp --dport <gpac_port> -s <trusted_network> -j ACCEPT
iptables -A INPUT -p tcp --dport <gpac_port> -j DROP