dbcve.org
Joomla\!Application · Joomla

CVE-2020-13763

HIGH · 7.5 CVSS v3.1 Published 2020-06-02
Fix available
A fix is available. Upgrade to 3.9.19 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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
In Joomla! before 3.9.19, the default settings of the global textfilter configuration do not block HTML inputs for Guest users.

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 · high confidence

In Joomla! before version 3.9.19, the default global textfilter configuration does not properly block HTML inputs for Guest (unauthenticated) users, potentially allowing Cross-Site Scripting (XSS) attacks through unfiltered HTML input submitted via forms.

MitigationUpdate Joomla to version 3.9.19 or later, and configure the global text filter settings to explicitly block or restrict HTML input for Guest user groups.

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:>= 2.5.1, < 3.9.19= 2.5.0

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
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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. Determine Joomla version
    Access the administrator backend and check the version from the help menu (About Joomla) or inspect the libraries/cms/version.php file for the VERSION constant
    Affected if Installed version is 2.5.0 or >= 2.5.1 but less than 3.9.19
  2. Verify Guest user group is in use
    Navigate to Users > Manage > Groups in the administrator panel and confirm a Guest group exists with ID 1 or is actively assigned to unauthenticated users
    Affected if A Guest user group exists in the system configuration
  3. Inspect global text filter settings for Guest group
    Go to System > Global Configuration > Text Filters, locate the filter settings assigned to the Guest user group, and check if the filter type allows or restricts HTML tags
    Affected if The text filter for the Guest user group is set to allow HTML (such as 'No Filtering' or similar permissive settings) rather than explicitly blocking HTML input

If Joomla version is below 3.9.19 and the text filter configuration for Guest users permits HTML input, the environment is vulnerable to XSS via unauthenticated form submissions.

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.

From vendor data
Upgrade available Upgrade to 3.9.19 or later
Fixed in 3.9.19
Interim mitigation

Update Joomla to version 3.9.19 or later, and configure the global text filter settings to explicitly block or restrict HTML input for Guest user groups.

Fix this in Joomla\! Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA2.0 h
7.0 hours of engineering $1,240
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2020-13763 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2020-13763 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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