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CVE-2026-48939CriticalCVSS 10.0CVE published 20 June 2026Added to mySites.guru 15 June 2026

iCagenda (com_icagenda) below 4.0.8 - Unauthenticated Arbitrary File Upload (RCE)

iCagenda's frontend "Submit an Event" form (index.php?option=com_icagenda&task=submit.submit) accepts arbitrary file uploads with no server-side type check. The submitAccess access-level setting is enforced only in the view, not on the processing path, so a guest with a freely-harvested CSRF token can upload a .php web shell to a web-served, predictable path and execute it, effectively unauthenticated RCE. Confirmed exploited in the wild from 15 Jun 2026 (icagenda-batch/1.0 scanner). CVE-2026-48939, added to the CISA Known Exploited Vulnerabilities catalog on 10 Jul 2026. Fixed in 4.0.8 (JoomliC Critical Security Release, 15 Jun 2026); update immediately. If you cannot patch, rename the com_icagenda component folders, since unpublishing does not close the hole.

Is my site affected?

CVE-2026-48939 is checked by 2 rules. Find the extension and release line your site runs:

ExtensionAffected versionsFixed inWhat to do
iCagendafrom 4.0.0 up to but not including 4.0.84.0.8Update iCagenda to 4.0.8 for this flaw, or to 4.0.12 or later, which no rule we check matches.
iCagendafrom 3.2.1 up to but not including 3.9.153.9.15Update iCagenda to 3.9.15 or later.
Check whether your sites are affected

How CVE-2026-48939 is scored

The base metrics as Joomla CNA published them, and what each one means for a site running an affected version. Threat and environmental metrics are left out: they describe a moment or a particular install rather than the flaw.

10.0 Critical

CVSS 4.0, scored by Joomla CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/AU:Y/U:Red

How it is reached

AV:N Attack vector
Network. Reachable across the internet
AC:L Attack complexity
Low. Nothing to work around, it just works
AT:N Attack requirements
None. Works against any affected install
PR:N Privileges required
None. No account needed
UI:N User interaction
None. Nobody has to be tricked into anything

What it does to the site

VC:H Confidentiality
High. Everything the site holds can be read
VI:H Integrity
High. Data and files can be altered at will
VA:H Availability
High. The site can be taken down

What it does beyond the site

SC:H Confidentiality
High. Data on other systems can be read
SI:H Integrity
High. Other systems can be altered
SA:H Availability
High. Other systems can be taken down

Timeline

  1. 15 June 2026mySites.guru check added for iCagenda (from 4.0.0 up to but not including 4.0.8)
  2. 15 June 2026mySites.guru check added for iCagenda (from 3.2.1 up to but not including 3.9.15)
  3. 15 June 2026We published: Zero Day Vulnerability Found in iCagenda Joomla Extension
  4. 20 June 2026CVE-2026-48939 record published by its CNA

Rule details

CriticalCVE-2026-489392026-06-15

iCagenda - iCagenda (com_icagenda) below 4.0.8 - Unauthenticated Arbitrary File Upload (RCE)

iCagenda's frontend "Submit an Event" form (index.php?option=com_icagenda&task=submit.submit) accepts arbitrary file uploads with no server-side type check. The submitAccess access-level setting is enforced only in the view, not on the processing path, so a guest with a freely-harvested CSRF token can upload a .php web shell to a web-served, predictable path and execute it, effectively unauthenticated RCE. Confirmed exploited in the wild from 15 Jun 2026 (icagenda-batch/1.0 scanner). CVE-2026-48939, added to the CISA Known Exploited Vulnerabilities catalog on 10 Jul 2026. Fixed in 4.0.8 (JoomliC Critical Security Release, 15 Jun 2026); update immediately. If you cannot patch, rename the com_icagenda component folders, since unpublishing does not close the hole.

Affected versions: ≥ 3.2.1 and < 3.9.15

Full advisory: our disclosure post

Our disclosure post

Zero Day Vulnerability Found in iCagenda Joomla Extension

Zero Day Vulnerability Found in iCagenda Joomla Extension

mySites.guru found and confirmed an unauthenticated upload giving remote code execution on Joomla 6 sites running iCagenda. Fixed same-day in 4.0.8.

Other vulnerabilities in iCagenda

Updating for CVE-2026-48939 alone can leave a site on a release another rule still matches. These are the other flaws we check for in the same extension.

iCagenda

Latest safe version: 4.0.12

References

CVE-2026-48939 questions

Which versions are affected by CVE-2026-48939?
CVE-2026-48939 is covered by 2 rules: iCagenda from 4.0.0 up to but not including 4.0.8; iCagenda from 3.2.1 up to but not including 3.9.15.
How do I fix CVE-2026-48939?
It depends on the extension and release line your site runs. For iCagenda from 4.0.0 up to but not including 4.0.8: update iCagenda to 4.0.8 for this flaw, or to 4.0.12 or later, which no rule we check matches. For iCagenda from 3.2.1 up to but not including 3.9.15: update iCagenda to 3.9.15 or later.
How severe is CVE-2026-48939?
Joomla CNA scores it 10.0 (Critical) under CVSS 4.0. In plain terms: reachable across the internet, no account needed and nobody has to be tricked into anything.

Running an affected version on a site you manage?

A free audit tells you which of your Joomla and WordPress sites run an affected version, which are out of date, and which have not been backed up. No card required. If a site is already compromised, fix.mysites.guru is a single fixed fee per incident, usually resolved the same day.

This check is part of the mySites.guru Joomla vulnerability scanner, which reads every installed extension's version on each audit. Browse the rest of the Joomla vulnerability database.

Rules current as of 5 October 2026.