CVE-2025-5283: Critical libvpx Vulnerability Threatens Chrome, Edge, and Firefox Users

A newly discovered critical vulnerability in the widely used libvpx video codec library (CVE-2025-5283) is putting millions of web browser users at risk. This use-after-free flaw, affecting Chrome, Edge, Firefox, and other browsers, could allow attackers to execute arbitrary code through specially crafted video content.

What is CVE-2025-5283?

The vulnerability resides in libvpx, an open-source video codec library developed by Google that provides VP8/VP9 video compression capabilities. Tracked as CVE-2025-5283, this high-severity flaw (CVSS score 8.8) stems from improper memory management when processing malformed video streams. Security researchers discovered that carefully crafted video content could trigger a use-after-free condition, potentially leading to remote code execution.

Affected Software and Versions

• Google Chrome: Versions prior to 125.0.6422.76
• Microsoft Edge: Versions prior to 125.0.2535.67
• Mozilla Firefox: Versions prior to 125.0.1
• Opera Browser: Versions prior to 105.0.4970.34
• Any other applications using vulnerable versions of libvpx (1.12.0 through 1.13.0)

How the Exploit Works

The vulnerability occurs during video stream processing when:
1. The browser parses a maliciously crafted VP8/VP9 video file
2. Memory allocated for video frame processing is improperly freed
3. Subsequent operations attempt to use this freed memory
4. This memory corruption can be leveraged for arbitrary code execution

Attack scenarios could include:
- Malicious video ads on legitimate websites
- Compromised video-sharing platforms
- Phishing emails with embedded video content
- Malicious video files shared via messaging apps

Current Threat Landscape

Security researchers have observed:
- Active exploitation attempts in the wild since early May 2025
- At least three distinct exploit chains being used
- Targeted attacks against journalists and activists in certain regions
- No widespread attacks reported yet, but the potential is significant

Mitigation and Patching

All major browser vendors have released updates addressing this vulnerability:

Recommended actions:
1. Immediately update your web browser to the latest version
2. Restart your browser after updating to ensure patches are applied
3. Consider temporarily disabling autoplay for video content
4. Be cautious when viewing video content from untrusted sources

Technical Deep Dive

The vulnerability stems from a race condition in libvpx's frame buffer management system. When processing certain VP9 video streams with specific temporal layer patterns, the code fails to properly maintain reference counts for frame buffers. This can lead to:

• Memory corruption in the browser's rendering process
• Potential bypass of sandbox protections in some configurations
• Information disclosure in failed exploitation attempts

Security researchers note that successful exploitation requires precise timing and specific memory layouts, making reliable attacks challenging but not impossible.

Enterprise Implications

For organizations, this vulnerability presents significant risks:

• Remote workforces: Employees accessing video conferencing platforms
• Marketing teams: Viewing video content from various sources
• Customer support: Handling video attachments from customers
• Public-facing systems: Digital signage using browser-based video

Enterprise mitigation strategies should include:

1. Immediate deployment of browser updates through existing management systems
2. Network-level controls to block known malicious video patterns
3. Enhanced monitoring for unusual browser crashes or behavior
4. Temporary restrictions on video content from untrusted domains

Historical Context

This isn't the first serious vulnerability in libvpx:

• 2022: CVE-2022-29245 (Memory corruption in VP9 decoding)
• 2021: CVE-2021-37973 (Use-after-free in VP8 processing)
• 2020: CVE-2020-6389 (Heap buffer overflow in VP9)

The frequency of these issues highlights the challenges in secure multimedia processing and the importance of:

• Regular code audits for multimedia libraries
• Improved fuzz testing of video codecs
• Better memory safety practices in low-level media processing

Future Protection Measures

Looking ahead, browser vendors and the libvpx community are working on:

1. Memory-safe rewrites: Portions of libvpx being rewritten in Rust
2. Enhanced sandboxing: Stronger isolation for media processing
3. Stricter validation: Additional checks for video stream headers
4. Automated testing: Expanded fuzzing coverage for edge cases

User Recommendations

Beyond immediate patching, users should:

• Enable automatic updates for their browsers
• Consider using browser extensions that block suspicious media content
• Be wary of unexpected video content, especially from unknown sources
• Monitor official channels for any updates about this vulnerability

The Bigger Picture

CVE-2025-5283 underscores several critical issues in modern web security:

1. The pervasive risk posed by fundamental multimedia components
2. The challenge of securing complex, performance-critical code
3. The growing attack surface as web applications handle more media formats
4. The need for coordinated disclosure and rapid patching across multiple vendors

As video continues to dominate web traffic, vulnerabilities in codecs like libvpx will remain high-value targets for attackers. This incident serves as a reminder that even trusted components in our daily browsing experience can harbor dangerous flaws waiting to be discovered.