CVE intelligence and bounded remediation

CVE-2021-24280 — Querysol Redirection For Contact Form 7 security vulnerability

High CVSS 8.8

In the Redirection for Contact Form 7 WordPress plugin before 2.3.4, any authenticated user, such as a subscriber, could use the import_from_debug AJAX action to inject PHP objects.

Severity
High
CVSS
8.8 (3.1)
Published
2021-05-14
CISA KEV
Not currently listed
Ecosystem
php/wordpress
Weaknesses
CWE-502

Affected products

  • querysol / redirection_for_contact_form_7

Matched remediation archetype

Unsafe deserialization and object reconstruction

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Check exposure

  • Inventory serialization formats accepted from requests, queues, caches, files, cookies, and cross-service messages.
  • Trace whether untrusted input can select classes, types, callbacks, constructors, or object hooks during decoding.
  • Identify signing, schema validation, trust-boundary, and compatibility settings for each decoder.

Remediate safely

  • Replace native object deserialization with a data-only format and explicit schema validation.
  • If replacement is not immediate, use a safe decoder with a minimal type allowlist and disable polymorphic or executable hooks.
  • Update the affected library and add inert tests for unknown types, extra fields, malformed nesting, and unsigned data.

Authoritative sources

Complete CVE record and remediation plan

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