Arbitrary file upload in Joomlaeventmanager.net Jem - Joomla Event Manager Extension For

CVE-2026-77991

Joomla Extension - joomlaeventmanager.net - Privileged remote code execution in Joomla Event Manager < 5.0.1 - The administrator source model allows to write dangerous file type incl. PHP, leading to remote code execution.

Vulnerability class: Unrestricted File Upload

Published · last modified .

EPSS exploit prediction

EPSS: 0.006 (49.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 49.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-77991: held from 0.004 to 0.006.

EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-77991?
CVE-2026-77991 is a vulnerability in Joomlaeventmanager.net Jem - Joomla Event Manager Extension For, classified under Unrestricted Upload of File with Dangerous Type. Published 2026-08-27.
Is CVE-2026-77991 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.