CVE-2026-42796
Unauthenticated RCE via /rest/configure; attacker-supplied plugin URL executes Python.
Is CVE-2026-42796 being exploited?
Not confirmed. CVE-2026-42796 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 2.7% probability of exploitation in the next 30 days.
How severe is CVE-2026-42796?
CVE-2026-42796 is rated Critical with a CVSS score of 9.2. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-42796?
Yes. A fix has been recorded for CVE-2026-42796. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-42796 affect?
CVE-2026-42796 affects Arelle web server (/rest/configure), Arelle < 2.39.10, Plugin manager (unauthenticated). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-42796?
Update to 2.39.10+; verify plugin sources
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution by loading attacker-controlled Python in the Arelle process via plugins parameter.
Patch when possible
- affected< 2.39.10
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.