critical CVSS 9.8 Actively exploited

CVE-2026-48939·PHP vulnerability

A vulnerability in the iCagenda extension for Joomla allows the upload of arbitrary files in the file attachment feature, ultimately resulting in PHP code upload and execution.

Severity
critical
Software
PHP
Fixed in
4.0.8
Published
2026-06-20

Affected versions

From: 4.0.0

Until: 4.0.8

Fixed in: 4.0.8

How to fix this CVE

The iCagenda extension for Joomla contains a critical file upload vulnerability that permits attackers to upload and execute arbitrary PHP code on affected servers. Immediately update the iCagenda extension to version 4.0.8 or later, which patches the unsafe file attachment handling. Verify that all file upload restrictions are properly enforced and audit your server logs for signs of malicious file uploads.

sudo dnf update php

Defensia detects this vulnerability

What an exploitation attempt looks like

Sample log line indicative of exploitation attempts:

POST /index.php?option=com_icagenda.*upload.*\.(php|phtml|php3|php4|php5|phar) HTTP/1.1|multipart/form-data.*filename=.*\.(php|exe|sh)

WAF mitigation (if patching is not yet possible)

Add this rule to your WAF to block exploitation attempts while you schedule the patch. 

Block POST requests to /index.php?option=com_icagenda with file uploads containing executable extensions (.php, .phtml, .php3, .php4, .php5, .phar, .exe, .sh). Implement strict MIME-type validation and reject uploads where Content-Type does not match the declared file extension.

How to check if you are affected

  1. Check your iCagenda extension version by navigating to Joomla Administrator > Extensions > Manage > Search for 'iCagenda' and note the version number displayed
  2. Verify if the attachment upload feature is active by checking if /components/com_icagenda/assets/uploads/ directory exists and contains files
  3. Search your web server logs for POST requests to icagenda upload endpoints: grep -r 'com_icagenda.*upload' /var/log/apache2/access.log or /var/log/nginx/access.log
  4. Confirm the patch is applied by verifying iCagenda version is 4.0.8 or higher through the Joomla extension manager interface

Indicators of compromise

  • POST requests to /index.php?option=com_icagenda with multipart form data containing .php files
  • Uploaded PHP files in /components/com_icagenda/assets/uploads/ directory
  • HTTP 200 responses to com_icagenda upload endpoints followed by subsequent GET requests to execute uploaded PHP

FAQ

What is CVE-2026-48939?

CVE-2026-48939 is a critical remote code execution vulnerability in the iCagenda Joomla extension that allows unauthenticated attackers to upload arbitrary files, including malicious PHP scripts, through the file attachment feature.

Is CVE-2026-48939 being actively exploited?

Yes, CVE-2026-48939 is actively exploited in the wild and is listed in CISA's Known Exploited Vulnerabilities catalog, indicating real-world attack activity.

What versions of iCagenda are affected by CVE-2026-48939?

iCagenda versions 4.0.0 through 4.0.7 are vulnerable; version 4.0.8 and later include the security fix.

How do I check if my Joomla installation is vulnerable to CVE-2026-48939?

Log into your Joomla Administrator panel, navigate to Extensions > Manage, search for 'iCagenda', and check if the version is below 4.0.8. If yes, your system is vulnerable.

Does Defensia detect CVE-2026-48939?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If iCagenda is installed on a monitored Joomla server, CVE-2026-48939 will appear in your dashboard with remediation steps.

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References

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