CVE-2026-6455
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 · uneditedThe WP Contact Form 7 DB Handler plugin for WordPress is vulnerable to Cross-Site Request Forgery leading to Arbitrary File Deletion via SQL Injection and PHP Object Injection in versions up to and including 3.0. This is due to a missing nonce verification in the process_bulk_action() function, the nonce check is only executed when _wpnonce is present in the POST body, allowing it to be trivially bypassed by omitting the field, combined with the use of an unsanitized, unparameterized user-supplied value in a numeric SQL context (WHERE ID = $ID) and the unsafe deserialization of the query result's post_content field. An attacker can craft a CSRF page that tricks a logged-in administrator into triggering a UNION-based SQL injection payload (using CHAR() to avoid esc_sql quote-escaping) that returns a malicious serialized PHP array as post_content; upon deserialization, array values associated with keys containing 'ys_cfdbh_file' are used as file paths appended to the uploads directory path without any path traversal validation, and then passed to wp_delete_file(), allowing the attacker to delete arbitrary files on the server (e.g., wp-config.php, system files).
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 confidenceThe WP Contact Form 7 DB Handler plugin has a CSRF vulnerability in process_bulk_action() where nonce verification is only performed when _wpnonce is present in the POST body, allowing trivial bypass by omitting the field. This is chained with an unsanitized SQL query using user input in a numeric context (WHERE ID = $ID) that enables UNION-based SQL injection. The injected SQL returns a malicious serialized PHP array as post_content, which is unsafely deserialized. Array values with keys containing 'ys_cfdbh_file' are used as file paths without path traversal validation, then passed to wp_delete_file(), enabling deletion of arbitrary files including wp-config.php.
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
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify plugin installation path and versionLocate the plugin directory (typically wp-content/plugins/contact-form-7-db-handler/ or similar named folder) and check the version in the plugin header comment in the main PHP file or in readme.txtAffected if The installed version lacks the patched nonce verification, parameterized queries, and path traversal validation in process_bulk_action()
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Verify plugin is activeQuery the WordPress database table wp_options for option_name='active_plugins' and check if the plugin folder name appears in the serialized arrayAffected if The plugin is active and the vulnerable code path is reachable
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Confirm process_bulk_action function existsSearch the plugin's main PHP file for the function 'process_bulk_action' and examine whether it performs nonce verification conditionally (only when _wpnonce is present)Affected if The function exists and contains conditional nonce checking that can be bypassed by omitting _wpnonce
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Check for unsafe deserialization patternSearch the plugin code for instances of 'unserialize()' applied to post_content or user-controlled data without prior validationAffected if The plugin deserializes data from the database without validating its structure first
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Identify file deletion functionalitySearch for calls to wp_delete_file() or similar file deletion functions that use array keys containing 'ys_cfdbh_file' as file paths without path traversal checksAffected if The code uses 'ys_cfdbh_file' keys as paths without validating for '../' sequences
The environment is affected if the WP Contact Form 7 DB Handler plugin is active, the installed version lacks proper nonce verification on all code paths in process_bulk_action(), and the plugin contains the unsafe deserialization and file deletion patterns described.
Generated from the published advisory. Verify against your own configuration.
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 dataUpgrade to a patched version that implements proper nonce verification on all code paths, uses parameterized queries/prepared statements, validates file paths against path traversal, and avoids unsafe deserialization of user-controlled data.
- Consultation5.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-6455 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-6455 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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