Incorrect handling of the GET params

[monteshot]

Preconditions and environment

Magento versions tested: 2.4.6-p12 and 2.4.8-p1

Issue: When incorrect parameters are sent, Magento 2 responds incorrectly (the exception is masked and not reflected in the response code).

Example URL:
https://443s--demo--248ce--demo.coder.perspectiveteam.com/push-it-messenger-bag.html?product=11508&selected_configurable_option=UhnG&related_product=xvON%2C%28%29%28%22%27%28%2E%2E%2C&item=11508&form_key=FF4VnOPZcMln2xlf&item_id=wgFd&qty=jvos

There is simple product processing with potentially hazardous parameters, for example:
qty=jvos

Under the hood, Magento sets data in PreconfiguredValues using data from buyRequest without validation:

\Magento\Wishlist\Plugin\Helper\Product\View::beforePrepareAndRender

\Magento\Catalog\Block\Product\View::getProductDefaultQty

I believe that setting the value in the Qty field should be performed only if qty is numeric.

Correct processing of this parameter (or possibly another parameter that causes the issue) would lead to proper cache behavior, since 5xx errors are not cached by default.

Steps to reproduce

Open any product and set the incorrect qty params on simple product

Expected result

M2 Returns 200(OK) code which can help prevent DDoS attack to the merchant

Actual result

M2 Returns 500 code which is one of the reasons of DDoS attack to the merchant

Additional information

Chrome dev tools

Potential solution

Release note

No response

Triage and priority

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

Hi @monteshot. Thank you for your report.
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[m2-assistant]

Hi @engcom-Bravo. Thank you for working on this issue.
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[engcom-Bravo]

Hi @monteshot,

Thanks for your reporting and collaboration.

We have tried to reproduce the issue in Latest 2.4-develop instance and we are able to reproduce the issue.Kindly refer the screenshots.

M2 Returns 500 Hence Confirming the issue.

Thanks.