Detect CVE-2026-41940: WebPros cPanel & WHM / WP2 Missing Authentication for Critical Function in Elastic Security
CVE-2026-41940 is an actively exploited missing authentication vulnerability (CWE-306) in WebPros cPanel & WHM and WP2 (WordPress Squared). Unauthenticated remote attackers can invoke critical administrative functions without valid credentials, enabling account takeover, malicious plugin installation, privilege escalation, and full server compromise. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.
MITRE ATT&CK
Elastic Detection Query
sequence by source.ip with maxspan=5m
[network where event.category == "network" and
http.request.method in ("GET", "POST") and
(
url.path like~ "*/json-api/*" or
url.path like~ "*/execute/*" or
url.path like~ "*/xmlapi/*" or
url.path like~ "*/wp-json/*"
) and
(
url.path like~ "*createacct*" or
url.path like~ "*removeacct*" or
url.path like~ "*passwd*" or
url.path like~ "*addpkg*" or
url.path like~ "*installplugin*" or
url.path like~ "*createuser*"
) and
http.response.status_code >= 200 and http.response.status_code < 400 and
(not exists(http.request.headers.authorization) or http.request.headers.authorization == "")]EQL sequence detection for unauthenticated requests to cPanel and WP2 critical administrative functions. Triggers on successful HTTP responses to sensitive endpoints lacking an Authorization header, indicative of CVE-2026-41940 exploitation.
Data Sources
Required Tables
False Positives & Tuning
- cPanel API token authentication may not populate the Authorization header in all versions and may use cookie-based sessions
- Internal scanner tools performing authenticated discovery that omit auth headers at certain probe stages
- Reverse proxies stripping Authorization headers before forwarding to the backend cPanel process
Other platforms for CVE-2026-41940
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1CVE-2026-41940 Unauthenticated cPanel Account Creation via JSON API
Expected signal: HTTP POST request to /json-api/createacct on port 2086 with HTTP 200 response and no Authorization header in web server access logs; corresponding cPanel audit log entry for account creation
- Test 2CVE-2026-41940 Unauthenticated Password Change via WHM XMLAPI
Expected signal: HTTP GET request to /xmlapi/passwd on port 2086 with HTTP 200 response visible in cPanel access logs; no session cookie or API token in request headers; cPanel audit log records password change event
- Test 3CVE-2026-41940 Unauthenticated WP2 Plugin Installation via WordPress REST API
Expected signal: HTTP GET and POST requests to /wp-json/wp/v2/plugins with HTTP 200/201 responses in web server access logs; WordPress debug log records plugin installation event; file system activity shows new directory creation under wp-content/plugins/
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