critical·Product Based Web Vulnerabilities·Updated Jul 23, 2026

CVE-2026-42796 Scanner

CVE-2026-42796 Scanner - Remote Code Execution vulnerability in Arelle

Est. Time~10 seconds
Scan TypeGroup Scan
Targetsurl
CostFree
0
Times Used
by S4E users
0
Assets Scanned
domains & IPs
0
Vulnerabilities Found
confirmed findings
References
CVECVE-2026-42796
9.2
CVSScritical
Exploitable remotely over the internet · no authentication required.

Arelle before 2.39.10 contains an unauthenticated remote code execution vulnerability in the /rest/configure REST endpoint that accepts a plugins query parameter and forwards it to the plugin manager without authentication or authorization. Attackers can supply a URL to a malicious Python file through the plugins parameter, causing the Arelle webserver to download and execute the attacker-controlled code within the Arelle process with its privileges.

Attack Vector
Network
Privileges Req.
None
User Interaction
None
Affected
Arelleby Arelle
AFFECTED< 2.39.10SAFE ✓≥ 2.39.10
Updated Aug 19, 2026View on NVD →
Detail

Arelle is an open-source project often used by financial analysts, accountants, and compliance officers for XBRL data analysis. It's a cross-platform tool that assists in the creation, validation, extraction, and conversion of XBRL (eXtensible Business Reporting Language) data. It provides a high level of flexibility and supports multiple implementations for operating the tool across various environments and use cases. The software can be integrated with custom scripts or utilized via its web server interface to support automated processing tasks. Due to its open-source nature, Arelle can be extended with additional plugins that can further enhance its functionality. It finds application in regulatory compliance, particularly in financial reporting and auditing sectors.

The Remote Code Execution vulnerability in Arelle allows unauthenticated attackers to execute arbitrary code within the host system. The flaw stems from mishandling a configuration endpoint in the web server component, /rest/configure, where unverified plugin URLs can be inserted. Attackers can provide a URL to a remote Python script which Arelle downloads and executes without authentication. This vulnerability can lead to severe security issues, including potential for full system compromise. Addressing this vulnerability requires updating Arelle to version 2.39.10 or later where such insecure plugin references are rejected. Maintainers have mobilized efforts to secure this endpoint and prevent unauthorized code execution.

The vulnerability primarily exists in the /rest/configure endpoint which inadequately verifies the 'plugins' query parameter. When a malicious URL is supplied, it directly forwards the request to Arelle's plugin management system, downloading and executing the Python file as a plugin. This execution ability allows attackers to inject and run arbitrary code with the server's privileges. The vulnerability remains a critical concern as it potentially grants attackers control over the entire host environment if exploited. Version updates beyond 2.39.10 phase out this security weakness by blocking illicit remote plugin URLs. It is crucial for users relying on remote plugins to immediately update their systems.

Exploitation of this vulnerability could lead to multiple severe impacts. A malicious attacker may gain unauthorized access and execute arbitrary code, allowing for data extraction, modification, or deletion. Given administrator privileges that may be associated, this could also facilitate a complete system takeover. Data confidentiality, integrity, and availability are all at stake, given the opportunity for attackers to plant persistent backdoors. Business continuity could be adversely affected with potential financial and reputational damages. Remediating this vulnerability is therefore essential to safeguard critical business operations and sensitive information.

REFERENCES

Solution Advice
  • Upgrade to Arelle version 2.39.10 or later to patch the vulnerability.
  • Ensure proper access control settings are in place, especially on critical endpoints.
  • Avoid exposing management interfaces directly to the internet without adequate protections.
  • Implement network segmentation to limit the impact of potential attacks.
  • Regularly audit and monitor plugin installations and configurations.

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