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PatchSiren cyber security CVE debrief

CVE-2026-48899 Joomla! Project CVE debrief

A medium-severity improper access control vulnerability in Joomla's com_users batch task allows authenticated users with limited privileges to escalate their permissions. The flaw exists in the sample data plugins component where access checks are incorrectly implemented during batch operations. Joomla versions 4.0.0 through 5.4.5 and 6.0.0 through 6.1.0 are affected. The vulnerability was disclosed by the Joomla Security Strike Team on May 26, 2026, with patches released in versions 5.4.6 and 6.1.1. No known exploitation in ransomware campaigns has been reported.

Vendor
Joomla! Project
Product
Joomla! CMS
CVSS
MEDIUM 5.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-26
Original CVE updated
2026-05-26
Advisory published
2026-05-26
Advisory updated
2026-05-26

Who should care

Joomla site administrators, web hosting providers, security teams managing CMS deployments, and organizations using Joomla for public-facing websites or internal applications

Technical summary

The vulnerability stems from incorrect access control checks in Joomla's sample data plugins when processing batch operations through the com_users component. An authenticated user with low privileges can manipulate batch task parameters to perform unauthorized actions, resulting in privilege escalation. The CVSS 4.0 score of 5.3 reflects network accessibility, low attack complexity, and required low privileges, with limited impacts to confidentiality, integrity, and availability. The flaw does not require user interaction and has no scope change.

Defensive priority

medium

Recommended defensive actions

  • Upgrade Joomla installations to version 5.4.6 or later for the 5.x branch, or 6.1.1 or later for the 6.x branch
  • Review user account permissions and audit recent batch operations performed through com_users
  • Apply principle of least privilege to user accounts with backend access
  • Monitor access logs for unusual batch task executions in com_users
  • If immediate patching is not possible, restrict access to the com_users component to trusted administrators only

Evidence notes

Vulnerability confirmed through official Joomla security advisory and NVD analysis. CVSS 4.0 vector indicates network attack vector with low attack complexity, requiring low privileges but no user interaction. CWE-284 (Improper Access Control) identified as primary weakness.

Official resources

2026-05-26