Executive Summary

CVE-2026-42601 is a Remote Code Execution (RCE) vulnerability in ArchiveBox versions 0.8.6rc0 and earlier. The issue exists in the /add/ endpoint, which accepts a JSON configuration field that is merged into the crawl configuration without any validation.

This unvalidated configuration is then exported as environment variables when archive plugins run, allowing attackers to inject arbitrary tool arguments. For example, attackers can override certain arguments to execute arbitrary commands on the server.

If the PUBLIC_ADD_VIEW setting is enabled, which is common for bookmarklet usage, the vulnerability can be exploited without authentication. Additionally, the endpoint is exempt from CSRF protection, making exploitation easier.

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Impact Analysis

This vulnerability allows an attacker to achieve full Remote Code Execution (RCE) on the ArchiveBox server.

An attacker can send crafted requests to the vulnerable endpoint to execute arbitrary commands, potentially compromising the entire server, accessing sensitive data, or disrupting services.

If the PUBLIC_ADD_VIEW setting is enabled, the attacker does not even need to authenticate, increasing the risk of exploitation.

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Detection Guidance

This vulnerability can be detected by monitoring for suspicious POST requests to the /add/ endpoint of the ArchiveBox server, especially those containing JSON config fields that override environment variables like YTDLP_ARGS_EXTRA or other plugin argument keys.

You can look for unusual commands being executed or unexpected files created on the server, such as files like /tmp/pwned, which may indicate exploitation attempts.

Example commands to detect exploitation attempts include:

• Using network monitoring tools (e.g., tcpdump or Wireshark) to filter POST requests to /add/: tcpdump -A -s 0 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep '/add/'
• Checking web server logs for POST requests to /add/ containing suspicious JSON payloads.
• Searching for files created by injected commands, e.g., ls -l /tmp/pwned
• Monitoring process execution logs or using tools like auditd to detect unexpected command executions related to yt-dlp or gallery-dl plugins.

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Mitigation Strategies

Immediate mitigation steps include disabling or restricting access to the /add/ endpoint, especially if the PUBLIC_ADD_VIEW setting is enabled.

Restricting network access to trusted users only and implementing authentication or IP whitelisting can reduce the risk of exploitation.

Since no patches are currently available, avoid enabling or using features that accept unvalidated config JSON inputs.

Monitor logs closely for suspicious activity and consider temporarily disabling plugins that rely on environment variables for arguments.

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Compliance Impact

The vulnerability CVE-2026-42601 allows remote code execution on the ArchiveBox server, potentially enabling attackers to execute arbitrary commands without authentication when certain settings are enabled.

Such a vulnerability could lead to unauthorized access, data breaches, or manipulation of archived data, which may impact compliance with data protection regulations like GDPR or HIPAA that require safeguarding sensitive information and ensuring system integrity.

However, the provided information does not explicitly discuss the direct effects on compliance with these standards.

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