Which SIEM platforms have a CVE-2026-48939 detection rule?

df00tech provides CVE-2026-48939 (iCagenda Unrestricted File Upload Exploitation (CVE-2026-48939)) detection queries for 7 SIEM platforms: Microsoft Sentinel / Defender, Splunk, Elastic Security (EQL), IBM QRadar (AQL), Sumo Logic CSE, Google Chronicle / SecOps, CrowdStrike LogScale (CQL).

What severity and confidence is the CVE-2026-48939 detection?

The CVE-2026-48939 detection is rated high severity with medium confidence.

What are common false positives for CVE-2026-48939?

Common false positives for CVE-2026-48939 include: Legitimate administrators uploading permitted image types via iCagenda backend; Vulnerability scanners performing authorized testing; Misconfigured monitoring tools polling the same URI patterns.

CVE-2026-48939 Sumo Logic CSE · Sumo

Detect iCagenda Unrestricted File Upload Exploitation (CVE-2026-48939) in Sumo Logic CSE

Q: What data sources are required to detect iCagenda Unrestricted File Upload Exploitation (CVE-2026-48939) (CVE-2026-48939)?

Detecting iCagenda Unrestricted File Upload Exploitation (CVE-2026-48939) requires the following data sources: IIS Logs, Web Server Logs, Azure WAF Logs.

Detects exploitation attempts against CVE-2026-48939, an Unrestricted Upload of File with Dangerous Type vulnerability (CWE-434) in the iCagenda Joomla component. Attackers abuse insufficient file-type validation in iCagenda's upload handlers (event image/attachment upload endpoints) to upload web shells or other executable content, achieving remote code execution on the underlying web server. This CVE is listed in CISA KEV, indicating confirmed active exploitation and mandated remediation under BOD 26-04.

MITRE ATT&CK

Tactic: Initial Access Execution

Sumo Detection Query

Sumo Logic CSE (Sumo)

sql

_sourceCategory=web/access
| where uri matches "*com_icagenda*" or uri matches "*icagenda*"
| where method="POST"
| where uri matches "*upload*" or uri matches "*attachment*" or uri matches "*image*"
| parse regex field=uri "(?<file_ext>\.[A-Za-z0-9]+)$"
| where file_ext matches "*php*" or file_ext matches "*phtml*" or file_ext matches "*phar*" or file_ext matches "*asp*" or file_ext matches "*jsp*" or status_code=200
| count by src_ip, uri, status_code, user_agent

high severity medium confidence

Sumo Logic search to surface anomalous POST uploads to iCagenda component endpoints with dangerous file extensions, mapped to CVE-2026-48939.

Data Sources

Web Server Access LogsCDN/WAF Logs

Required Tables

web/access

False Positives & Tuning

Legitimate CMS media management activity
Third-party monitoring bots crawling similar paths
Authorized red-team validation traffic

Other platforms for CVE-2026-48939

Microsoft Sentinel (KQL) Splunk (SPL) Elastic Security (Elastic) IBM QRadar (QRadar) Google Chronicle (YARA-L) CrowdStrike LogScale (LogScale) All platforms (combined) →

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 1Simulate malicious PHP upload to iCagenda endpoint
Expected signal: Web server access log entry showing POST to com_icagenda upload path with HTTP 200 response, followed by a new file creation event in the media/com_icagenda upload directory
Test 2Verify uploaded shell executability
Expected signal: GET request to the uploaded PHP file logged, followed by php-fpm/apache2 spawning a child process (id) consistent with web shell command execution
Test 3Windows IIS-hosted Joomla upload simulation
Expected signal: W3C IIS log entry recording POST to com_icagenda upload endpoint with dangerous .aspx extension and 200 status

Last updated: 2026-07-11 Research depth: standard

References (4)

Response Playbook

Triage

Confirm the target host runs Joomla with the iCagenda component installed and check the installed version against the vendor's fixed release at icagenda.com/#download
Search web server access logs for POST requests to com_icagenda upload/attachment/image endpoints returning HTTP 200, especially followed by GET requests to the same uploaded filename
Inspect the web root and iCagenda upload/media directories for recently created files with executable extensions (.php, .phtml, .phar, .jsp, .asp) or files disguised with double extensions
Check for outbound connections or unusual process spawning from the web server process (php-fpm, apache2, w3wp.exe) shortly after suspicious uploads, indicating a web shell was executed

Containment

Immediately restrict or disable public write access to iCagenda upload directories, and if feasible take the vulnerable component offline until patched
Deploy or update WAF rules to block POST requests to com_icagenda upload endpoints containing executable file extensions or MIME-type mismatches

Evidence Collection

Preserve uploaded files, web server access/error logs, and file system timestamps (creation/modification) for the affected upload directories
Capture a memory and process snapshot of the web server host if a web shell execution or lateral movement is suspected

Escalation Criteria

!Escalate to incident response if a web shell or unauthorized executable file is confirmed on the server, or if outbound C2-like traffic is observed from the web host
!Escalate if the affected Joomla instance hosts sensitive data, is internet-facing with elevated privileges, or shows signs of lateral movement to internal systems

Investigation Guide

Related Techniques

[object Object][object Object]

Forensic Artifacts

>Web server access logs showing POST requests to com_icagenda upload endpoints and subsequent GET requests to the uploaded file
>Files with dangerous extensions (.php, .phtml, .jsp, .asp) present in iCagenda media/upload directories
>Web server process (apache2, php-fpm, w3wp.exe) spawning unexpected child processes (cmd.exe, bash, whoami, id) shortly after an upload event
>Joomla component database entries referencing iCagenda events with attachments not matching expected content types

Tuning Guidance

Baseline legitimate iCagenda administrative upload activity (expected file types: jpg, png, gif, pdf, docx) to reduce noise, and tune extension-matching rules to your organization's actual Joomla directory structure. If the WAF or proxy strips/rewrites URIs, adjust field extraction accordingly. Consider suppressing alerts from known internal vulnerability scanner IP ranges performing authorized testing.

Hunting Queries

Broad hunt across web logs for any request (upload or subsequent access) referencing dangerous executable extensions within iCagenda component paths, useful for retroactive compromise assessment.

Hunting — KQL

kql

W3CIISLog | where csUriStem has "com_icagenda" | where csUriStem matches regex @"\.(php\d?|phtml|phar|pht|asp|aspx|jsp)$" | project TimeGenerated, cIP, csUriStem, scStatus

Hunting — SPL

spl

index=web_logs uri="*com_icagenda*" | regex uri="\.(php\d?|phtml|phar|pht|asp|aspx|jsp)$" | table _time, src_ip, uri, status

Atomic Red Team Tests

Test 1 Simulate malicious PHP upload to iCagenda endpoint

linux

Simulates an attacker uploading a PHP web shell disguised as an event attachment through the iCagenda upload endpoint in a lab Joomla instance.

Command

bash

curl -s -X POST -F "[email protected];type=image/jpeg" http://LAB-TARGET/index.php?option=com_icagenda&task=upload.attachment

Cleanup

bash

rm -f /var/www/html/media/com_icagenda/uploads/shell.php; find /var/www/html -name 'shell*' -delete

Expected Telemetry

Web server access log entry showing POST to com_icagenda upload path with HTTP 200 response, followed by a new file creation event in the media/com_icagenda upload directory

Expected Detection

KQL/SPL rule flags the POST request due to dangerous file extension despite MIME-type spoofing

Test 2 Verify uploaded shell executability

linux

Confirms that an uploaded PHP file in the iCagenda media directory can be executed via direct web request, validating the RCE impact chain in a lab environment.

Command

bash

curl -s http://LAB-TARGET/media/com_icagenda/uploads/shell.php?cmd=id

Cleanup

bash

rm -f /var/www/html/media/com_icagenda/uploads/shell.php; service apache2 restart

Expected Telemetry

GET request to the uploaded PHP file logged, followed by php-fpm/apache2 spawning a child process (id) consistent with web shell command execution

Expected Detection

Process-creation and hunting query correlating web server child-process spawn with prior suspicious upload event

Test 3 Windows IIS-hosted Joomla upload simulation

windows

Simulates the same iCagenda upload exploitation against a lab Joomla site hosted on Windows/IIS to validate cross-platform log coverage.

Command

powershell

Invoke-WebRequest -Uri "http://LAB-TARGET/index.php?option=com_icagenda&task=upload.attachment" -Method POST -InFile 'C:\lab\shell.aspx' -ContentType 'multipart/form-data'

Cleanup

powershell

Remove-Item 'C:\inetpub\wwwroot\media\com_icagenda\uploads\shell.aspx' -Force

Expected Telemetry

W3C IIS log entry recording POST to com_icagenda upload endpoint with dangerous .aspx extension and 200 status

Expected Detection

KQL query against W3CIISLog flags the upload based on extension match and endpoint pattern

Detect iCagenda Unrestricted File Upload Exploitation (CVE-2026-48939) in Sumo Logic CSE

MITRE ATT&CK

Sumo Detection Query

Data Sources

Required Tables

False Positives & Tuning

Other platforms for CVE-2026-48939

Testing Methodology

Response Playbook

Triage

Containment

Evidence Collection

Escalation Criteria

Investigation Guide

Related Techniques

Forensic Artifacts

Tuning Guidance

Hunting Queries

Atomic Red Team Tests

Command

Cleanup

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Command

Cleanup

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Command

Cleanup

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Related Detections

Tactic Hubs

Related Techniques

Same Tactic: Initial Access

Popular Detections

MITRE ATT&CK

Sumo Detection Query

Data Sources

Required Tables

False Positives & Tuning

Other platforms for CVE-2026-48939

Testing Methodology

Response Playbook

Triage

Containment

Evidence Collection

Escalation Criteria

Investigation Guide

Related Techniques

Forensic Artifacts

Tuning Guidance

Hunting Queries

Atomic Red Team Tests

Command

Cleanup

Expected Telemetry

Expected Detection

Command

Cleanup

Expected Telemetry

Expected Detection

Command

Cleanup

Expected Telemetry

Expected Detection

Related Detections

Tactic Hubs

Related Techniques

Same Tactic: Initial Access

Popular Detections

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