Detect CVE-2026-41940: WebPros cPanel & WHM / WP2 Missing Authentication for Critical Function in Sumo Logic CSE
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
Sumo Detection Query
_sourceCategory=web/access/cpanel OR _sourceCategory=web/access/nginx OR _sourceCategory=web/access/apache OR _sourceCategory=web/access/iis
| parse regex "(?<src_ip>\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3})" nodrop
| parse regex "\"(?<method>GET|POST|PUT|DELETE|PATCH)\s+(?<uri>/[^\s\"]*)" nodrop
| parse regex "\s(?<status_code>\\d{3})\s" nodrop
| parse regex "\"(?<user_agent>[^\"]+)\"\s*$" nodrop
| where uri matches "*/json-api/*" or uri matches "*/execute/*" or uri matches "*/xmlapi/*" or uri matches "*/wp-json/*"
| where uri matches "*createacct*" or uri matches "*removeacct*" or uri matches "*passwd*" or uri matches "*addpkg*" or uri matches "*installplugin*" or uri matches "*createuser*"
| where num(status_code) >= 200 and num(status_code) < 400
| count by src_ip, uri, method, status_code
| where _count >= 1
| sort by _count desc
| fields src_ip, uri, method, status_code, _countSumo Logic query to detect CVE-2026-41940 exploitation attempts against cPanel & WHM and WP2 administrative API endpoints. Parses web access logs for unauthenticated successful requests to critical functions.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate cPanel UAPI calls from hosting automation platforms that authenticate via session tokens not visible in raw access logs
- CDN or load balancer request forwarding where the original client authentication context is stripped from log fields
- Internal management scripts that appear unauthenticated in web tier logs but carry valid cPanel session cookies
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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