Spam Protection\, Antispam\, FirewallWordPress extension · Cleantalk
CVE-2023-51535
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 · uneditedCross-Site Request Forgery (CSRF) vulnerability in СleanTalk - Anti-Spam Protection Spam protection, Anti-Spam, FireWall by CleanTalk.This issue affects Spam protection, Anti-Spam, FireWall by CleanTalk: from n/a through 6.20.
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 confidenceA Cross-Site Request Forgery (CSRF) vulnerability exists in the CleanTalk Anti-Spam plugin for WordPress (versions through 6.20). The vulnerability allows attackers to trick authenticated administrators into performing unintended actions via maliciously crafted requests, potentially leading to configuration changes or spam protection bypass.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Spam Protection\, Antispam\, FirewallWordPress extension
<= 6.20CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 checksWork through these to decide whether this CVE applies to you.
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Identify CleanTalk plugin installation and versionNavigate to WordPress admin dashboard > Plugins > Installed Plugins. Locate 'Cleantalk Spam Protection' and check the version number displayed. Alternatively, check the plugin's main PHP file header or version.php for the version constant.Affected if The installed version is 6.20 or lower.
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Locate plugin administrative formsIn the WordPress plugins directory (wp-content/plugins/cleantalk-spam-protection), search for PHP files containing form tags with method="post" or functions that handle administrative actions (settings, configuration updates). Common files include admin.php, settings.php, or files in an 'admin' subfolder.Affected if The plugin processes administrative actions without verified nonce tokens.
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Inspect form submissions for nonce fieldsOpen the identified form-handling PHP files. Search for instances of wp_nonce_field, wp_nonce_url, or check_admin_referer. Verify that these nonce functions are called on all forms that perform state-changing operations.Affected if Forms that modify plugin settings or configuration lack nonce field generation or server-side verification.
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Check AJAX endpoints for nonce validationSearch for add_action('wp_ajax_') or add_action('wp_ajax_nopriv_') calls within the plugin. For each AJAX handler, verify that the handler calls wp_verify_nonce or check_admin_referer before processing the request.Affected if AJAX endpoints that handle administrative actions do not validate nonces before executing.
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Verify nonce validation execution orderIn the identified form handlers and AJAX endpoints, confirm that nonce verification occurs BEFORE any database updates, configuration changes, or privileged operations are performed.Affected if Nonce checks are missing or occur after the sensitive operations have already executed.
A user is affected if they have CleanTalk Spam Protection plugin version 6.20 or lower installed AND the plugin's administrative forms or AJAX endpoints lack proper nonce verification before processing state-changing requests.
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 dataImplement anti-CSRF tokens (nonces) on all state-changing forms and AJAX endpoints within the plugin, and verify the nonce validation on the server side before processing any administrative actions.
Fix this in Spam Protection\, Antispam\, Firewall
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-51535 — 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-2023-51535 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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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.
- 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