# CVE-2026-42796: Arelle < 2.39.10 Unauthenticated RCE via /rest/configure

> Unauthenticated attackers can execute arbitrary code by supplying a malicious URL to the /rest/configure endpoint in Arelle.

- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 May 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-m48p-vcj6-wq3j

## What is CVE-2026-42796?

CVE-2026-42796 is a critical code injection vulnerability in Arelle, published on 4 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-42796?

It affects 1 product.


Products: Workiva Arelle.

## How do I fix CVE-2026-42796?

No fix has been published for CVE-2026-42796 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-42796 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42796 exists.

Public exploit code:

- https://github.com/ameerhamza-malik/CVE-2026-42796 (github_poc): https://github.com/ameerhamza-malik/CVE-2026-42796
- Arelle < 2.39.10 - Remote Code Execution (nuclei): http/cves/2026/CVE-2026-42796.yaml

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42796 and fix it if it is affected.

What it is: CVE-2026-42796 is a critical code injection vulnerability in Arelle, published on 4 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42796 exists.

Affected product: Arelle. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42796/ (Markdown: https://insights.sbomify.com/CVE-2026-42796/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42796
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42796
- OSV: https://osv.dev/vulnerability/CVE-2026-42796

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42796/
Summaries are generated and may contain mistakes; the official description above is the record.