dbcve.org
Improper AuthenticationWeakness · CWE-287

CVE-2026-1305

MEDIUM · 5.3 CVSS v3.1 Published 2026-02-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
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 Japanized for WooCommerce plugin for WordPress is vulnerable to Improper Authentication in versions up to, and including, 2.8.4. This is due to a flawed permission check in the `paidy_webhook_permission_check` function that unconditionally returns `true` when the webhook signature header is omitted. This makes it possible for unauthenticated attackers to bypass payment verification and fraudulently mark orders as "Processing" or "Completed" without actual payment via a crafted POST request to the Paidy webhook endpoint.

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 Japanized for WooCommerce plugin has an improper authentication vulnerability in its Paidy webhook handler. The `paidy_webhook_permission_check` function unconditionally returns `true` when the webhook signature header is omitted, allowing unauthenticated attackers to bypass payment verification via crafted POST requests. This enables fraudulent modification of order statuses to 'Processing' or 'Completed' without actual payment.

MitigationUpdate to version 2.8.5 or later which implements proper signature validation. Until patched, consider disabling the Paidy webhook endpoint or adding server-side validation to verify the signature header is present and valid.

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
None
Integrity
Low
Availability
None

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

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. Locate and identify the Japanized for WooCommerce plugin version
    Access your WordPress site via FTP or file manager and navigate to wp-content/plugins/. Look for the plugin directory (commonly named 'woocommerce-for-japan' or similar). Open the main plugin PHP file to read the version number declared in the plugin header comment.
    Affected if The installed version is lower than 2.8.5 (the fixed version).
  2. Confirm Paidy payment gateway is enabled in WooCommerce
    Log into WordPress admin and go to WooCommerce > Settings > Payments. Check if Paidy is listed among enabled payment methods and if it is toggled to 'Enabled'.
    Affected if The Paidy payment gateway is enabled and active in WooCommerce.
  3. Inspect the paidy_webhook_permission_check function
    In the plugin directory, locate the file handling Paidy webhooks (typically in includes/ or classes/ folder). Open the file and find the 'paidy_webhook_permission_check' function. Examine whether it performs any validation on the signature header before returning true.
    Affected if The function returns true unconditionally when the signature header is missing or empty, without performing any validation.
  4. Check if signature header validation exists in the webhook handler
    Review the webhook processing code in the Paidy handler file. Look for code that retrieves and validates the webhook signature header (commonly checked via $_SERVER['HTTP_X_PAIDY_SIGNATURE'] or similar). Verify if valid signatures are rejected when absent.
    Affected if No code exists to validate that the signature header is present and correct before processing the webhook request.

Your environment is affected if the Japanized for WooCommerce plugin version is below 2.8.5 AND the Paidy payment gateway is enabled, because the webhook handler unconditionally accepts requests missing the signature validation.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update to version 2.8.5 or later which implements proper signature validation. Until patched, consider disabling the Paidy webhook endpoint or adding server-side validation to verify the signature header is present and valid.

Recommended fix Moderate confidence

Upgrade to a version newer than 2.8.4 (check WordPress Plugin Repository for latest stable release)

  1. Check the current version of the Japanized for WooCommerce plugin installed on your WordPress site
  2. Navigate to Plugins > Installed Plugins in the WordPress admin dashboard
  3. Locate Japanized for WooCommerce and note the current version number
  4. Visit the WordPress Plugin Repository at plugins.trac.wordpress.org to check for any newer releases beyond version 2.8.4
  5. If a newer version (after 2.8.4) is available, update the plugin via Plugins > Add New > Upload or directly through the WordPress updates interface
  6. After updating, verify that the paidy_webhook_permission_check function now properly validates the signature header before processing webhook requests
  7. Monitor order statuses in WooCommerce to ensure orders are not being marked as Processing or Completed without valid Paidy payment confirmation

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-1305 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2026-1305 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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
  • No spam, self-promotion, credentials, or personal data