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CWE-345Weakness · CWE-345

CVE-2026-11901

MEDIUM · 5.3 CVSS v3.1 Published 2026-07-11
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 6 weeks old

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 WP Hotel Booking plugin for WordPress is vulnerable to Insufficient Verification of Data Authenticity in all versions up to, and including, 2.3.1. This is due to the `web_hook_process_paypal_standard()` IPN handler selecting its PayPal validation endpoint from the attacker-controlled `$_REQUEST['test_ipn']` parameter, force-upgrading any `pending` transaction to `completed` when `test_ipn=1`, and omitting post-verification checks on `receiver_email`, `mc_currency`, and `txn_id` uniqueness after receiving a `VERIFIED` response from PayPal. This makes it possible for unauthenticated attackers to mark arbitrary hotel bookings as fully paid without submitting genuine payment to the merchant — either by routing IPN validation through PayPal's sandbox using a free sandbox account, or by replaying a previously verified IPN from a nominal payment to an attacker-controlled PayPal account. An attacker requires only a free PayPal sandbox account (or any PayPal account) to obtain a `VERIFIED` response; no site credentials or special configuration are needed.

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 WP Hotel Booking plugin's PayPal IPN handler (`web_hook_process_paypal_standard()`) allows attackers to select the PayPal validation endpoint via the attacker-controlled `$_REQUEST['test_ipn']` parameter, forces pending transactions to completed when `test_ipn=1`, and skips critical post-verification checks on receiver_email, mc_currency, and txn_id uniqueness after receiving a VERIFIED response. This enables unauthenticated attackers to mark arbitrary hotel bookings as paid using a free PayPal sandbox account.

MitigationRemove user control over the PayPal validation endpoint, eliminate the force-complete logic for test_ipn, and implement proper verification of receiver_email, mc_currency, and txn_id uniqueness after PayPal verification.

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. Confirm WP Hotel Booking plugin is installed
    Access WordPress admin dashboard, navigate to Plugins > Installed Plugins, or inspect plugin directory at /wp-content/plugins/wp-hotel-booking/ for existence of plugin files
    Affected if Plugin is installed and active in WordPress
  2. Verify PayPal Standard payment method is enabled
    Check plugin settings: Hotel Booking > Settings > Payments tab, look for PayPal Standard or similar PayPal payment option and confirm it is active
    Affected if PayPal Standard payment gateway is enabled in the plugin configuration
  3. Locate the vulnerable IPN handler function
    Inspect plugin source files for function named web_hook_process_paypal_standard() - typically found in /includes/gateways/paypal-standard/ directory or similar gateway include files
    Affected if Function web_hook_process_paypal_standard() exists in the plugin code
  4. Inspect code for test_ipn parameter handling
    Open the IPN handler file and search for $_REQUEST['test_ipn'] or $_GET['test_ipn'] usage, verify if user input controls PayPal validation endpoint URL
    Affected if The code uses $_REQUEST['test_ipn'] to determine PayPal validation endpoint without sanitization
  5. Check for skipped post-verification validation
    Examine the code after receiving VERIFIED response from PayPal - look for absence of receiver_email, mc_currency, and txn_id uniqueness validation checks
    Affected if The IPN handler lacks proper receiver_email verification, mc_currency validation, and txn_id duplicate checking after PayPal verification

Your environment is affected if WP Hotel Booking plugin is installed with PayPal Standard enabled AND the web_hook_process_paypal_standard() function handles test_ipn without proper validation checks.

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

Remove user control over the PayPal validation endpoint, eliminate the force-complete logic for test_ipn, and implement proper verification of receiver_email, mc_currency, and txn_id uniqueness after PayPal verification.

Recommended fix Moderate confidence

Latest version of WP Hotel Booking plugin (version higher than 2.3.1)

  1. 1. Backup your WordPress site before making any changes
  2. 2. Navigate to Plugins > Installed Plugins in WordPress admin dashboard
  3. 3. Locate the WP Hotel Booking plugin
  4. 4. Check the current version number to confirm it is 2.3.1 or below
  5. 5. If an update is available, click 'Update Now' to install the latest version
  6. 6. After updating, verify the plugin version has changed to confirm the update was successful
  7. 7. Test the PayPal payment functionality to ensure bookings can still be processed correctly
  8. 8. Review PayPal IPN settings in the plugin to confirm test_ipn parameter handling is no longer vulnerable

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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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-2026-11901 in production — separate from our analysis above.

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