Deserialization of Untrusted DataWeakness · CWE-502

CVE-2025-8871

MEDIUM · 5.6 CVSS v3.1 Published 2025-11-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
65/100
Remediation priority · Elevated
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
The Everest Forms (Pro) plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 1.9.7 via deserialization of untrusted input in the mime_content_type() function. This makes it possible for unauthenticated attackers to inject a PHP Object. This vulnerability may be exploited by unauthenticated attackers when a form is present on the site with a non-required signature form field along with an image upload field. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present. This vulnerability is only exploitable in PHP versions prior to 8.

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 Everest Forms Pro plugin for WordPress is vulnerable to PHP Object Injection via deserialization of untrusted input in the mime_content_type() function. Unauthenticated attackers can exploit this when a form contains both a non-required signature field and an image upload field, and the site runs PHP versions prior to 8. Without a POP chain present in other plugins or themes, the impact is limited.

MitigationUpdate Everest Forms Pro to version 1.9.8 or later, and upgrade to PHP 8+ to eliminate the vulnerability entirely. Audit for plugins/themes with exploitable POP chains as a defense-in-depth measure.

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

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

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 Everest Forms Pro is installed
    In WordPress admin, go to Plugins > Installed Plugins and look for Everest Forms Pro. Note the installed version number displayed there.
    Affected if Everest Forms Pro is installed with a version below 1.9.8
  2. Confirm PHP version
    Check your server PHP version via phpinfo(), a plugin like WP Server Stats, or by running `php -v` on the command line.
    Affected if PHP version is 7.x or lower (PHP 8 and later are not affected)
  3. Identify forms with both signature and image upload fields
    In WordPress admin, go to Everest Forms > All Forms. For each form, edit it and check if it contains both a Signature field (added via the Signature add-on) and an Image Upload field. Verify whether the Signature field is marked as required or not.
    Affected if A form contains a non-required (optional) Signature field AND an Image Upload field simultaneously

You are affected if Everest Forms Pro is installed below version 1.9.8, your server runs PHP below version 8, AND a form exists with both a non-required signature field and an image upload field.

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

Update Everest Forms Pro to version 1.9.8 or later, and upgrade to PHP 8+ to eliminate the vulnerability entirely. Audit for plugins/themes with exploitable POP chains as a defense-in-depth measure.

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-8871 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2025-8871 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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