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.

CVSS v4.0

9.2 CRITICALCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1

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

EPSS

2.75% chance of exploitation in the next 30 days, 85th percentile

Nuclei

critical · CWE-306

Published

2026-05-04

Updated

2026-07-14

Proof-of-concept exploits (1)

• ameerhamza-malik/CVE-2026-427960★ · 2026-05-08

Nuclei templates (1)

• projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-42796.yaml

References

• CVE Record
• NVD entry

Related

• CVE-2026-42785
• CVE-2026-42809
• CVE-2026-42779
• CVE-2026-42826
• CVE-2026-42778
• CVE-2026-4284