CVE-2025-69771: asbplayer v1.13.0 RCE Vulnerability

CVE-2025-69771 Overview

An arbitrary file upload vulnerability exists in the subtitle loading function of asbplayer v1.13.0 that allows attackers to execute arbitrary code via uploading a crafted subtitle file. This vulnerability falls under CWE-434 (Unrestricted Upload of File with Dangerous Type), enabling remote code execution through specially crafted malicious subtitle files.

Critical Impact

Attackers can achieve remote code execution by exploiting the subtitle loading function, potentially compromising user systems through malicious subtitle files distributed via social engineering or compromised subtitle repositories.

Affected Products

• asbplayer v1.13.0
• Chrome browser extension versions using vulnerable asbplayer components

Discovery Timeline

• 2026-02-25 - CVE-2025-69771 published to NVD
• 2026-02-26 - Last updated in NVD database

Technical Details for CVE-2025-69771

Vulnerability Analysis

This vulnerability resides in the subtitle loading function of asbplayer, a popular browser extension used for language learning with video content. The flaw allows attackers to bypass file type restrictions when uploading subtitle files, enabling the execution of arbitrary code on the victim's system.

The vulnerability is network-accessible and requires user interaction—typically the victim must load a malicious subtitle file. Due to the changed scope characteristic, successful exploitation can impact resources beyond the vulnerable component, potentially affecting the underlying browser or system.

Root Cause

The root cause of this vulnerability is improper validation of uploaded subtitle files (CWE-434 - Unrestricted Upload of File with Dangerous Type). The subtitle loading function fails to properly sanitize or restrict the types of files that can be processed, allowing attackers to craft subtitle files containing executable payloads. This lack of input validation in the file upload handling mechanism permits dangerous file types to be processed as legitimate subtitles.

Attack Vector

The attack vector is network-based, requiring user interaction to trigger the vulnerability. An attacker can exploit this flaw by:

1. Crafting a malicious subtitle file containing executable code or payloads disguised as legitimate subtitle content
2. Distributing the malicious file through subtitle sharing platforms, compromised websites, or social engineering tactics
3. Waiting for a victim to load the crafted subtitle file using the vulnerable asbplayer extension
4. Achieving code execution when the subtitle loading function processes the malicious file without proper validation

The vulnerability mechanism involves the subtitle parser accepting and executing content that should be restricted to safe subtitle data formats. For detailed technical analysis of this vulnerability, refer to the Tistory Offensive Analysis which provides in-depth exploitation details.

Detection Methods for CVE-2025-69771

Indicators of Compromise

• Unusual file types or oversized subtitle files (.srt, .ass, .vtt) being loaded by asbplayer
• Unexpected process spawning or network connections originating from browser processes after loading subtitle files
• Suspicious JavaScript execution or extension behavior following subtitle file import
• Anomalous browser extension activity or permission requests from asbplayer

Detection Strategies

• Monitor browser extension activity for unexpected file operations or code execution patterns
• Implement file integrity monitoring on subtitle files before processing
• Deploy endpoint detection rules to identify malicious payload execution from browser contexts
• Analyze network traffic for suspicious connections initiated after subtitle loading operations

Monitoring Recommendations

• Enable detailed logging for browser extension activities and file operations
• Configure alerts for anomalous process creation from browser contexts
• Monitor for known malicious subtitle file signatures or patterns
• Implement behavioral analysis to detect code execution attempts from media-related extensions

How to Mitigate CVE-2025-69771

Immediate Actions Required

• Disable or remove asbplayer v1.13.0 until a patched version is available
• Avoid loading subtitle files from untrusted or unknown sources
• Review browser extension permissions and restrict file access capabilities
• Educate users about the risks of loading subtitle files from unverified sources

Patch Information

No official vendor patch has been confirmed at this time. Users should monitor the official asbplayer repository and the Killer Gerbah Blog for security updates. Consider upgrading to newer versions if patches become available.

Workarounds

• Disable the subtitle loading functionality in asbplayer until a fix is released
• Use alternative subtitle loading methods or applications with proper file validation
• Implement browser-level restrictions to prevent arbitrary file execution from extensions
• Configure Content Security Policy (CSP) settings to limit extension capabilities
• Manually validate subtitle files before loading by inspecting their contents for suspicious code

# Disable asbplayer extension temporarily via Chrome policies
# Add to chrome://policy or group policy settings
{
  "ExtensionInstallBlocklist": ["asbplayer-extension-id"]
}