CVE-2025-54300HighCVSS 8.5Published 25 August 2025

Quantum Manager (com_quantummanager) below 3.2.1 - Stored XSS (SVG upload and filename)

Quantum Manager file manager. CVE-2025-54300 (unsanitised SVG upload) and CVE-2025-54301 (unescaped file names) lead to stored XSS. Affects 1.0.0-3.2.0, fixed in 3.2.1.

Affected versions: < 3.2.1

Official record: cve.org · NVD

Every connected Joomla site is checked against this rule on each audit, and flagged if it runs an affected version.

Check whether your sites are affected

How CVE-2025-54300 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.

8.5 High

CVSS 4.0, scored by Joomla CNA

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H

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:H Privileges required: High. Needs an account with elevated rights
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:N Integrity: None. Nothing can be altered
VA:N Availability: None. The site stays up

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

Affected extensions and versions

HighCVE-2025-54300 CVE-2025-543012025-08-25

Quantum Manager

Affected versions: < 3.2.1

Full advisory: nvd.nist.gov

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A free audit tells you which of your Joomla and WordPress sites run an affected version, which are out of date, and which have not been backed up.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.

Rules current as of 3 October 2026.