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Deserialization of Untrusted DataWeakness · CWE-502

CVE-2025-9260

MEDIUM · 6.5 CVSS v3.1 Published 2025-09-03
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable 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
The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to PHP Object Injection in versions 5.1.16 to 6.1.1 via deserialization of untrusted input in the parseUserProperties function. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject a PHP Object. The additional presence of a POP chain allows attackers to read arbitrary files. If allow_url_include is enabled on the server, remote code execution is possible. While the vendor patched this issue in version 6.1.0, the patch caused a fatal error in the vulnerable code, due to a missing class import, so we consider 6.1.2 to be the most complete and best patched version

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

The Fluent Forms WordPress plugin versions 5.1.16 through 6.1.1 contain a PHP Object Injection vulnerability in the parseUserProperties function through unsafe deserialization of untrusted input. Authenticated attackers with Subscriber-level access can inject PHP objects. When combined with a POP chain present in the application, this enables arbitrary file read; with allow_url_include enabled, remote code execution becomes possible.

MitigationUpgrade to Fluent Forms version 6.1.2 or later immediately to remediate this vulnerability. If immediate patching is not feasible, consider restricting or disabling subscriber-level access until the patch can be applied.

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

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/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. Verify Fluent Forms plugin is installed and identify version
    In WordPress admin, go to Plugins > Installed Plugins and locate Fluent Forms. The version number is displayed there. Alternatively, check the plugin header in /wp-content/plugins/fluentform/main/fluentform.php or via WP-CLI: wp plugin list --name=fluent-forms
    Affected if The installed version is 5.1.16, 5.1.17, 5.1.18, 5.1.19, 5.1.20, 5.1.21, 6.0.0, 6.0.1, 6.0.2, 6.0.3, 6.0.4, 6.0.5, 6.0.6, 6.1.0, or 6.1.1 (any version from 5.1.16 through 6.1.1 inclusive)
  2. Confirm user registration or subscriber access is enabled
    In WordPress admin, go to Settings > General and check "Membership" setting "Anyone can register" with a default role of Subscriber. Also check for any user with the Subscriber role under Users > All Users
    Affected if Anyone can register is enabled with Subscriber as the default role, or any Subscriber-level accounts exist on the site
  3. Identify if Fluent Forms user submission features are accessible
    Check if Forms have user property fields enabled or if there are forms that accept user-submitted data that gets processed by the parseUserProperties function. Review form entries or form builder settings in Fluent Forms
    Affected if Forms are configured to accept and process user properties input that flows through the parseUserProperties function
  4. Check PHP allow_url_include setting
    Create a PHP info file (info.php) with content: <?php phpinfo(); ?> and access it via browser, or run: php -i | grep allow_url_include from command line. Look for the allow_url_include directive value
    Affected if allow_url_include is set to On (enabled)
  5. Check for POP chain gadgets in installed plugins or theme
    Review all active plugins and the active theme for classes with magic methods (__wakeup, __destruct, __toString, __get, __set) that could form a POP chain. Use a code analysis tool or manually search plugin directories for these magic methods
    Affected if Active plugins or theme contain exploitable POP chain gadgets that could be chained with the PHP Object Injection

You are affected if Fluent Forms version is between 5.1.16 and 6.1.1 AND subscriber-level access exists on the site AND forms using parseUserProperties are accessible to subscribers.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Fluent Forms version 6.1.2 or later immediately to remediate this vulnerability. If immediate patching is not feasible, consider restricting or disabling subscriber-level access until the patch can be applied.

Recommended fix High confidence

Fluent Forms version 6.1.2

  1. 1. Navigate to WordPress admin dashboard > Plugins section
  2. 2. Locate the Fluent Forms plugin in the installed plugins list
  3. 3. Click on 'Update now' if an update is available, or manually upload version 6.1.2 from the WordPress plugin repository
  4. 4. Verify the plugin updated successfully to version 6.1.2 or later
  5. 5. Confirm the site functions normally after the update
  6. 6. As a hardening measure, ensure allow_url_include is disabled in php.ini if not required for site functionality

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

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
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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-2025-9260 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
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