Deserialization of Untrusted DataWeakness · CWE-502

CVE-2025-49393

CRITICAL · 9.8 CVSS v3.1 Published 2025-11-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
Deserialization of Untrusted Data vulnerability in Fetch Designs Sign-up Sheets sign-up-sheets allows Object Injection.This issue affects Sign-up Sheets: from n/a through <= 2.3.2.

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

This is a PHP Object Injection vulnerability in the Fetch Designs Sign-up Sheets WordPress plugin. The plugin deserializes untrusted data without proper validation, allowing authenticated or unauthenticated attackers to inject malicious PHP objects. When paired with magic methods in the plugin or other installed plugins, this can lead to remote code execution.

MitigationUpgrade to a patched version of the Sign-up Sheets plugin (version 2.3.3 or higher). Until a patch is available, disable the plugin or implement WAF rules to block deserialization-related attack patterns.

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

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

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 plugin version
    In WordPress admin, go to Plugins > Installed Plugins > Sign-up Sheets, or inspect the plugin main file header for 'Version:' value. Alternatively, check wp-content/plugins/sign-up-sheets/readme.txt for the Stable tag.
    Affected if version is lower than 2.3.3 or the version cannot be determined (unknown)
  2. Verify plugin is active
    Confirm the Sign-up Sheets plugin is enabled in WordPress (Plugins > Installed Plugins). Check the wp_options table for 'active_plugins' option containing 'sign-up-sheets'.
    Affected if plugin is installed and active
  3. Identify deserialization usage in plugin code
    Search plugin source files for 'unserialize()' function calls, particularly in files handling form submissions, AJAX requests, or AJAX callbacks within wp-content/plugins/sign-up-sheets/.
    Affected if unserialize() calls exist in the plugin code processing user input
  4. Check for untrusted data deserialization
    Examine the plugin files identified in step 3 to see if unserialize() is called on data from $_POST, $_GET, $_REQUEST, or database values that could be controlled by users.
    Affected if unserialize() processes any input originating from user requests or external sources
  5. Inspect plugin entry points for unauthenticated access
    Review plugin AJAX handlers and public-facing forms to determine if they can be accessed without authentication. Check for 'nopriv' capability in add_action calls or absence of auth checks.
    Affected if plugin endpoints accepting user data are accessible without authentication

The environment is affected if the Sign-up Sheets plugin version is below 2.3.3 AND the plugin contains unserialize() calls that process untrusted user input, especially via unauthenticated endpoints.

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

Upgrade to a patched version of the Sign-up Sheets plugin (version 2.3.3 or higher). Until a patch is available, disable the plugin or implement WAF rules to block deserialization-related attack patterns.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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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-2025-49393 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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