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Joomla\!Application · Joomla

CVE-2026-25900

MEDIUM · 6.1 CVSS v3.1 Published 2026-05-26
Fix available
A fix is available. Upgrade to 5.4.6 / 6.1.1 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Lack of output escaping leads to a XSS vector in the feed modules.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A Cross-Site Scripting (XSS) vulnerability exists in feed modules due to insufficient output escaping. User-supplied or stored data rendered in RSS/Atom feeds or similar feed functionality is not properly encoded, allowing injection of malicious HTML/JavaScript that executes in victim browsers.

MitigationImplement context-appropriate output encoding (HTML entity encoding, URL encoding) for all data rendered in feed output. Validate and sanitize input at entry points, then apply output escaping at render time.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Joomla\!Application
Affected:>= 3.0.0, < 5.4.6>= 6.0.0, < 6.1.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Joomla version
    Locate the version.php file in your Joomla installation (typically at /libraries/src/Version.php or check the administrator manifest), or access the Joomla administrator dashboard and look at System > Information or Help > System Info
    Affected if The installed version is >= 3.0.0 and < 5.4.6, OR >= 6.0.0 and < 6.1.1
  2. Identify feed modules in use
    In Joomla administrator, go to Extensions > Modules and search for or filter for 'feed' type modules, or inspect the filesystem for modules using 'feed' in the name under /modules/
    Affected if Feed modules are published and serving content on the site
  3. Check for user-generated content sources
    Review which components feed modules consume content from (such as news feeds, custom content, or third-party integrations) by examining the module parameters in Extensions > Modules > [Feed Module]
    Affected if Feed modules are configured to display content that originates from user submissions, external feeds, or stored database content
  4. Verify output escaping in feed module templates
    Inspect the default feed module template files in /modules/mod_[feedname]/tmpl/ or custom template overrides in /templates/[templatename]/html/mod_[feedname]/ for proper use of HTML escaping functions like htmlspecialchars() or Joomla's JHtml::_('grid.string')
    Affected if User-controllable data in feeds is rendered without proper encoding/escaping functions

You are affected if your Joomla version falls within the vulnerable ranges AND you have feed modules enabled that display user-supplied or stored content without output escaping.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.4.6 / 6.1.1 or later
Fixed in 5.4.66.1.1
Interim mitigation

Implement context-appropriate output encoding (HTML entity encoding, URL encoding) for all data rendered in feed output. Validate and sanitize input at entry points, then apply output escaping at render time.

Recommended fix High confidence

Joomla 5.4.6 or Joomla 6.1.1 (depending on your current branch)

  1. 1. Create a complete backup of the Joomla site including files and database
  2. 2. Set up a staging environment to test the upgrade
  3. 3. Upgrade Joomla to version 5.4.6 (if on 5.x branch) or 6.1.1 (if on 6.x branch)
  4. 4. Clear any caching systems
  5. 5. Verify the feed modules function correctly and that the XSS vulnerability is resolved
  6. 6. Monitor for any extension compatibility issues
Caveat Major version upgrades may have breaking changes; test extensively in staging first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Joomla\! Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-25900 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data