Auth bypass in Arelle
CVE-2026-42796
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.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.039 (89.9th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 90th percentile — 89.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.027 · newest: 0.039 · change: +0.011
Affected products
- Arelle — versions 0
- Workiva Arelle
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/Arelle/Arelle/releases/tag/2.39.10 (release-notes, Release Notes, patch)
- github.com/Arelle/Arelle/pull/2320 (issue-tracking, Patch, Issue Tracking)
- www.vulncheck.com/advisories/arelle-unauthenticated-rce-via-rest-configure (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-42796?
- CVE-2026-42796 is a critical-severity vulnerability in Arelle, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2026-05-04.
- How severe is CVE-2026-42796?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2026-42796 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.