Detect CVE-2026-48908 - JoomShaper SP Page Builder Unrestricted File Upload in Elastic Security
Detects exploitation of CVE-2026-48908, an unrestricted file upload vulnerability (CWE-434) in JoomShaper SP Page Builder for Joomla. Attackers can upload files with dangerous types (e.g., PHP webshells) through the page builder interface, leading to remote code execution. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.
MITRE ATT&CK
- Tactic
- Initial Access Execution Persistence
Elastic Detection Query
sequence by source.ip with maxspan=5m
[network where event.category == "network" and
http.request.method : "POST" and
url.path : "*/components/com_sppagebuilder*" and
http.response.status_code in (200, 201, 202)]
[file where event.action in ("creation", "overwrite") and
file.path : ("*/components/com_sppagebuilder/*", "*/uploads/*", "*/media/*") and
file.extension : ("php", "php3", "php4", "php5", "php7", "phtml", "phar", "asp", "aspx", "jsp", "cgi", "pl", "py", "sh", "bash")]]
| filter sequence[0].http.request.body.content : "*filename*" or
sequence[0].url.query : "*upload*"EQL sequence detecting a network POST to SP Page Builder upload endpoint followed by creation of a file with a dangerous extension, indicating successful webshell upload via CVE-2026-48908.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate plugin or theme file uploads by administrators via the SP Page Builder interface
- File integrity monitoring generating events on known-good file deployments
- Staging/development environments where developers upload test PHP files
Other platforms for CVE-2026-48908
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 1Unauthenticated PHP Webshell Upload via SP Page Builder
Expected signal: Web server access log entry: POST /index.php?option=com_sppagebuilder&task=file.upload HTTP/1.1 200; multipart/form-data body containing filename=shell.php with PHP content
- Test 2Double Extension Bypass Upload Attempt
Expected signal: POST request to SP Page Builder upload endpoint with filename containing double extension (.php.jpg); web server logs showing 200 response and file write event to upload directory
- Test 3Webshell Execution Verification Post-Upload
Expected signal: Web server access log entries: GET /images/shell.php HTTP/1.1 200; process execution events showing php-fpm or apache spawning child processes (id, hostname, uname); potential outbound network connections from web server process
References (4)
- https://extensions.joomla.org/extension/sp-page-builder/
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-48908
Unlock Pro Content
Get the full detection package for CVE-2026-48908 including response playbook, investigation guide, and atomic red team tests.