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ArelleApplication · Workiva

CVE-2026-42796

CRITICAL · 9.8 CVSS v3.1 Published 2026-05-04
Fix available
A fix is available. Upgrade to 2.39.10 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

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

MitigationUpgrade Arelle to version 2.39.10 or later to remediate this vulnerability. If immediate patching is not feasible, implement network-level restrictions to block unauthorized access to the /rest/configure endpoint from untrusted networks.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
ArelleApplication
Affected:< 2.39.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Arelle installation and version
    Locate the Arelle installation and determine its version by checking the installed package version or the executable version. Compare this version number against the affected range (versions before 2.39.10).
    Affected if The installed version is lower than 2.39.10
  2. Determine if the web server interface is enabled
    Check whether the Arelle web server (REST API interface) is currently running or has been enabled. This is typically controlled via command-line flags or configuration files.
    Affected if The Arelle web interface is enabled and accessible on any network interface
  3. Verify network accessibility of the /rest/configure endpoint
    Check if port 8080 (default Arelle web port) or the configured web server port is listening and accessible. Attempt to access the /rest/configure endpoint from a remote system or check the listening configuration.
    Affected if The /rest/configure endpoint is reachable from untrusted networks without authentication
  4. Confirm lack of authentication on the REST API
    Inspect the Arelle configuration for any authentication or authorization settings applied to the REST endpoints, particularly /rest/configure.
    Affected if No authentication or authorization controls are configured for the REST API interface

A user is affected if Arelle version is below 2.39.10 AND the web server interface is enabled with the /rest/configure endpoint accessible without authentication.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.39.10 or later
Fixed in 2.39.10
Vendor patch github.com →
Interim mitigation

Upgrade Arelle to version 2.39.10 or later to remediate this vulnerability. If immediate patching is not feasible, implement network-level restrictions to block unauthorized access to the /rest/configure endpoint from untrusted networks.

Recommended fix High confidence

2.39.10 or later

  1. 1. Back up your current Arelle installation and configuration files.
  2. 2. Identify your current Arelle version by checking the installation or running 'arelleCmdLine --version' if available.
  3. 3. Download Arelle version 2.39.10 or later from the official GitHub releases: https://github.com/Arelle/Arelle/releases
  4. 4. Install the new version following the standard installation method for your platform (pip install, Docker, or direct extraction).
  5. 5. Verify the upgrade was successful by checking the installed version.
  6. 6. Restart the Arelle webserver service if it was running.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Arelle Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-42796 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data