CVE-2026-29058: Wwbn Avideo-encoder RCE Vulnerability

CVE-2026-29058 Overview

CVE-2026-29058 is a critical command injection vulnerability in AVideo Encoder, a video-sharing platform software developed by WWBN. Prior to version 7.0, an unauthenticated attacker can execute arbitrary OS commands on the server by injecting shell command substitution into the base64Url GET parameter. This vulnerability is classified as CWE-78 (Improper Neutralization of Special Elements used in an OS Command).

Critical Impact

This vulnerability enables full server compromise through unauthenticated remote command execution, potentially leading to data exfiltration of configuration secrets, internal keys, and credentials, as well as complete service disruption.

Affected Products

• wwbn avideo-encoder (versions prior to 7.0)

Discovery Timeline

• 2026-03-06 - CVE CVE-2026-29058 published to NVD
• 2026-03-10 - Last updated in NVD database

Technical Details for CVE-2026-29058

Vulnerability Analysis

This command injection vulnerability exists in AVideo Encoder's handling of user-supplied input through the base64Url GET parameter. The application fails to properly sanitize or validate input before passing it to operating system command execution functions. An unauthenticated attacker can exploit this flaw by crafting malicious requests containing shell command substitution syntax (such as backticks or $() constructs) within the base64Url parameter. When the application processes this parameter, the injected commands are executed with the privileges of the web server process.

The exploitation requires no authentication, making this vulnerability particularly dangerous as it is accessible to any network attacker who can reach the vulnerable endpoint. Successful exploitation grants the attacker the ability to run arbitrary commands on the underlying operating system, effectively providing remote code execution capabilities.

Root Cause

The root cause of this vulnerability is improper input validation and inadequate sanitization of the base64Url GET parameter before it is used in OS command execution contexts. The application does not properly neutralize special shell metacharacters and command substitution sequences, allowing attackers to break out of the intended command context and inject their own commands.

Attack Vector

The attack is network-based and requires no user interaction or prior authentication. An attacker can craft a malicious HTTP GET request containing command substitution payloads in the base64Url parameter. When processed by the vulnerable endpoint, these commands execute on the server with the web application's privileges.

The attack flow typically involves:

1. Identifying the vulnerable endpoint that processes the base64Url parameter
2. Crafting a payload using shell command substitution syntax
3. Sending the malicious request to the target server
4. The injected commands execute, potentially establishing persistent access

Detection Methods for CVE-2026-29058

Indicators of Compromise

• Unusual HTTP GET requests containing shell metacharacters ($(), backticks, ;, |, &) in the base64Url parameter
• Unexpected outbound network connections from the web server process
• Creation of unauthorized user accounts or SSH keys on the server
• Anomalous process spawning from the web server process (e.g., /bin/sh, wget, curl, nc)
• Unexplained modifications to system files or web application configuration

Detection Strategies

• Deploy web application firewall (WAF) rules to detect and block command injection patterns in GET parameters
• Monitor web server access logs for requests containing shell metacharacters in URL parameters
• Implement anomaly detection for web server process behavior, alerting on unusual child process creation
• Use endpoint detection and response (EDR) solutions to identify command execution chains originating from web processes

Monitoring Recommendations

• Enable verbose logging for the AVideo Encoder application to capture all incoming requests
• Monitor system calls made by the web server process for suspicious command execution patterns
• Set up alerts for file integrity monitoring on critical system and configuration files
• Implement network traffic analysis to detect potential data exfiltration following exploitation

How to Mitigate CVE-2026-29058

Immediate Actions Required

• Upgrade AVideo Encoder to version 7.0 or later immediately
• If immediate patching is not possible, consider taking the vulnerable application offline until the update can be applied
• Review server logs for signs of prior exploitation and investigate any suspicious activity
• Rotate any credentials or API keys that may have been exposed on compromised systems
• Implement network segmentation to limit the impact of potential server compromise

Patch Information

The vulnerability has been addressed in AVideo Encoder version 7.0. Organizations should update to this version or later to remediate the vulnerability. Additional details are available in the GitHub Security Advisory GHSA-9j26-99jh-v26q.

Workarounds

• Deploy a web application firewall (WAF) with rules to block command injection attempts targeting the base64Url parameter
• Implement strict input validation at the network perimeter to reject requests containing shell metacharacters
• Restrict network access to the AVideo Encoder application to trusted IP addresses only
• Run the application in a containerized or sandboxed environment to limit the impact of potential exploitation