Add vpatch-CVE-2026-31816 rule and test

[crowdsec-automation]

This rule detects the Budibase authentication bypass vulnerability (CVE-2026-31816) by matching requests where the full URL (including query string) contains the webhook pattern /webhooks/trigger. The vulnerability is triggered when an attacker crafts a request with this pattern in the query string, which is improperly matched by the server's authorization middleware, allowing unauthenticated access to protected endpoints.

• The rule uses the URI_FULL zone to ensure the pattern is detected anywhere in the full URL, including the query string.
• The lowercase and urldecode transforms are applied to ensure case-insensitive and encoded variants are detected.
• The contains match type is used for flexibility, as the pattern may appear anywhere in the query string.
• No additional AND/OR logic is used, as only the presence of the pattern is required for detection.
• The labels section includes the correct CVE, ATT&CK, and CWE references.

Validation checklist:

• All value: fields are lowercase.
• transform includes lowercase and urldecode.
• No match.value contains capital letters.
• Rule uses contains instead of regex where applicable.

[github-actions]

Hello @crowdsec-automation and thank you for your contribution!

❗ It seems that the following scenarios are not part of the 'crowdsecurity/appsec-virtual-patching' collection:

🔴 crowdsecurity/vpatch-CVE-2026-31816 🔴

[github-actions]

Hello @crowdsec-automation and thank you for your contribution!

I'm a bot that helps maintainers to validate scenarios and ensure they include all the required information.
I've found some errors in your scenarios, please fix them and re-submit your PR, or ask for help if you need it.

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crowdsecurity/crs-exclusion-plugin-cpanel:

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crowdsecurity/crs-exclusion-plugin-dokuwiki:

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crowdsecurity/crs-exclusion-plugin-drupal:

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crowdsecurity/crs-exclusion-plugin-nextcloud:

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crowdsecurity/crs-exclusion-plugin-phpbb:

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crowdsecurity/crs-exclusion-plugin-phpmyadmin:

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crowdsecurity/crs-exclusion-plugin-wordpress:

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crowdsecurity/crs-exclusion-plugin-xenforo:

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Mitre ATT&CK

Information about mitre attack can be found here.
As an example, some common mitre attack techniques:

• T1110 for bruteforce attacks
• T1595 and T1190 for exploitation of public vulnerabilities
• T1595 for generic scanning of exposed applications

Expected format is (where XXXX is the technique ID):

labels:
  classification:
    - attack.TXXXX

CVEs

If your scenario covers a specific CVE (Common Vulnerabilities and Exposures), please add it.

Expected format is (where CVE-XXX-XXX is the CVE ID):

labels:
  classification:
    - cve.CVE-XXX-XXX

Behaviors

Please identify the behavior(s) your scenario is targeting. You can find the list of available behaviors here.

Expected format is (where <behavior> is the behavior you want to target):

labels:
  behavior: <behavior>

See the labels documentation for more information.