Customer Login Page is incorrectly cached with private data if Magento Captcha isn't enabled

[collymore]

Preconditions and environment

• Version 2.4.7

Steps to reproduce

• Disable the module Magento_Captcha, there is no dependancy on this module and the Magento_Customer module, so the Customer Login page should work correctly.
• Visit the Customer Account login page "/customer/account/login" with Full page cache active

Expected result

The page returns FPC MISS.

The customer account form is using private data e.g The current Customer Email address is output in the forms login field" and this shouldn't be cached.

Actual result

The page response is returned with a Full page cache HIT.

If visiting the page after a cache clear and logged in, the email will be cached on the page for all subsequent requests.

Additional information

The only reason that the Customer Account Login page is not cached by default is the Magento_Captcha module's layout customer_account_login.xml file.

This is adding a bock name="captcha" to the container name="form.additional.info".
That block has cacheable="false" declared which then stops the login page from being cached.

Without this module activate nothing else is making the page non-cacheable.

Edit : This issue actually effects every Customer Account Form

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 @collymore. Thank you for your report.
To speed up processing of this issue, make sure that the issue is reproducible on the vanilla Magento instance following Steps to reproduce.

• For more details, review the Magento Contributor Assistant documentation.
• Add a comment to assign the issue: @magento I am working on this
• To learn more about issue processing workflow, refer to the Code Contributions.

---

Join Magento Community Engineering Slack and ask your questions in #github channel.
⚠️ According to the Magento Contribution requirements, all issues must go through the Community Contributions Triage process. Community Contributions Triage is a public meeting.
🕙 You can find the schedule on the Magento Community Calendar page.
📞 The triage of issues happens in the queue order. If you want to speed up the delivery of your contribution, join the Community Contributions Triage session to discuss the appropriate ticket.

[m2-assistant]

Hi @engcom-Delta. Thank you for working on this issue.
In order to make sure that issue has enough information and ready for development, please read and check the following instruction: 👇

• 1. Verify that issue has all the required information. (Preconditions, Steps to reproduce, Expected result, Actual result).
• 2. Verify that issue has a meaningful description and provides enough information to reproduce the issue.
• 3. Add Area: XXXXX label to the ticket, indicating the functional areas it may be related to.
• 4. Verify that the issue is reproducible on 2.4-develop branch
  Details

  - If the issue is reproducible on 2.4-develop branch, please, add the label Reproduced on 2.4.x.
  - If the issue is not reproducible, add your comment that issue is not reproducible and close the issue and stop verification process here!
• 5. Add label Issue: Confirmed once verification is complete.
• 6. Make sure that automatic system confirms that report has been added to the backlog.

[engcom-Delta]

Hi @collymore ,

Thanks for your reporting and collaboration.
We have tried to reproduce the issue in Latest 2.4-develop instance, but we can see there is dependency in disabling Magento_Captcha module. Kindly refer the screenshots.

Can you please provide more steps that will help in replicating the issue.

Thanks.

[collymore]

Hi,
Yes it was disabled with -f to force the disabling. Or if the child container="form.additional.info" from without the forms xml layout is removed.

I did a loom video.
https://www.loom.com/share/427a8fa2083b48c8a940482e7acead19?sid=e06655ae-d521-4bfb-9f6d-586657f88483