Public accessibility of cron.php causes errors and security concerns

[Gurdit]

Preconditions and environment

Magento / Adobe Commerce 2.4.8

Steps to reproduce

1. Install Magento 2
2. Open a browser and navigate to https://yourdomain.com/cron.php.

Expected result

1. cron.php should not be publicly accessible in a production environment.
2. Magento cron jobs should only run via CLI (bin/magento cron:run) and system cron tasks.

Actual result

1. cron.php is exposed to the web by default.
2. If executed via HTTP, it can cause runtime errors, e.g.: TypeError: implode(): Argument #1 ($array) must be of type array, string given in /app/bvu7cj4frt2um/vendor/magento/module-cron/Observer/ProcessCronQueueObserver.php:967

Additional information

• cron.php exposure appears to be a legacy carryover from Magento 1, where web crons were common on shared hosting.
• Current Adobe Commerce documentation recommends system-level CLI cron only (bin/magento cron:run).
• Executing cron.php via HTTP can cause errors (e.g. implode(): Argument #1 ($array) must be of type array, string given) and may unnecessarily increase the attack surface.
• In modern deployments, cron.php is not required, but its presence in pub/ causes confusion about best practices.
• Clarification is needed whether this file should be considered deprecated or officially supported.

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.
• [x] 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”.

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[devchris79]

You should have an entry in .htaccess (within pub folder) that prevents cron.php execution, like this:

https://github.com/magento/magento2/blob/c8ff03033f9d79d9e6b6482086940153a28c6443/pub/.htaccess#L225-L234

[WebHostingAce]

@Gurdit, If you are running on NGINX, convert the .htaccess rules into the corresponding NGINX configuration.

[engcom-Bravo]

@devchris79 @WebHostingAce Thanks for your Contribution!!

Hi @Gurdit,

Thanks for your reporting and collaboration.

Could you please refer the above comments https://github.com/magento/magento2/issues/40190#issuecomment-3285755135 https://github.com/magento/magento2/issues/40190#issuecomment-3290172608 and please let us know if you are still facing any issue.

Thanks.

[koushikch7]

Possible Strategies / Fixes

You’ll have to choose a path depending on your constraints (hosting, infra, CDNs, etc.). Below are options; I’ll also sketch a sample patch.

Strategy	Pros	Cons / Risks
Block HTTP access via web server (Apache / Nginx rules)	Simple, doesn’t require code change. Can return 403/404 for cron.php via HTTP.	Requires control of server config. Might block legitimate HTTP calls if any custom use.
In-code guard in cron.php itself	Self-protecting: if accessed via HTTP, exit early or redirect.	cron.php may be overwritten in upgrades; you must maintain patch.
Remove/disable cron.php file in pub/ (or root) via installation process	Eliminates the endpoint entirely.	Some legacy plugins might expect it; may break fallback, legacy workflows.
Wrap cron-logic so HTTP execution fails safely	Even if cron.php is invoked, it doesn’t crash (fails silently or safe exit).	Adds overhead and complexity; must ensure no side effects.
Documentation / deprecation / backward-compatibility announcement	Sets expectations for users; upstream can follow with official removal.	Doesn’t solve in existing deployed sites; reactive.

---

Sketching a Patch / Guard Logic

If you go with the in-code guard approach, place early checks in pub/cron.php before executing the core cron logic:

<?php
// pub/cron.php (or root/cron.php) — Patch start
// If request is via HTTP (i.e. $_SERVER['REQUEST_METHOD'] is set), block it
if (php_sapi_name() !== 'cli' && isset($_SERVER['REQUEST_METHOD'])) {
// Option A: send 404
header("HTTP/1.1 404 Not Found");
exit;
</span><span><span class="hljs-comment">// Option B: send 403 Forbidden</span></span><span>
</span><span><span class="hljs-comment">// header("HTTP/1.1 403 Forbidden");</span></span><span>
</span><span><span class="hljs-comment">// exit;</span></span><span>

}
// ... rest of normal cron.php logic

Additionally, wrap around parts where arrays or implode is used, to avoid runtime errors when input is malformed:

// Example where implode is used: make sure input is array
$someVar = /* whatever source */;
if (!is_array($someVar)) {
    $someVar = []; // or cast / convert
}
$joined = implode(',', $someVar);

The key is: short-circuit HTTP requests.

---

Alternative Server-Level Blocks

Apache (.htaccess inside pub/)

<Files "cron.php">
    Require all denied
</Files>

Nginx

location = /cron.php {
    deny all;
    return 404;
}

---

Steps You’d Take (Practical)

1. Identify exactly where cron.php resides in your Magento setup (root/cron.php or pub/cron.php).

2. Decide whether your environment allows server config changes.

   • If yes → block at Apache/Nginx level (preferred, cleaner).

   • If no → patch cron.php with in-code guard.

3. If patching, keep it in a diff file or patch folder so it’s version-controlled.

4. Add unit / integration tests (if possible) for HTTP vs CLI invocation.

5. Deploy to staging first, then verify:

   • curl https://yourdomain.com/cron.php gives 404/403 or no execution.

   • Cron tasks via CLI (bin/magento cron:run) still run as expected.

   • No side effects in other flows.

6. For completeness, consider filing a pull request (if your change is generic) or join discussion upstream to deprecate/remove the public cron.php.

[engcom-Bravo]

@koushikch7 Thanks for your Contribution!!.

Hi @Gurdit,

Kindly refer the above comment and please let us know if you are still facing any issue.

Thanks.

[hostep]

Would be good to know if anybody still relies on the pub/cron.php file to exist, because in my opinion nobody should rely on it and we should simply remove it from the codebase.

[engcom-Hotel]

Hello @Gurdit,

Thanks for the report and collaboration!

We have tried to reproduce the issue in the latest development branch i.e. 2.4-develop but the issue is not reproducible for us in both Apache and Nginx.

Both gives us 404 page not found error as below:

Please try to reproduce the issue in the 2.4-develop branch and let us know if we missed anything.

Thank you

[engcom-Hotel]

Hello @Gurdit,

Gentle reminder for this issue.

Thank you

[engcom-Hotel]

Would be good to know if anybody still relies on the pub/cron.php file to exist, because in my opinion nobody should rely on it and we should simply remove it from the codebase.

I agree with @hostep's comment above, I think it is not recommended to use the web version of cron.php, hence confirming this issue.

Hello @Gurdit,

Thank you for bringing this issue to our attention. If you have a potential solution, we encourage you to submit a pull request. Your contributions significantly enhance Magento Open Source for everyone. Should you need any assistance, please don't hesitate to ask!

[github-jira-sync-bot]

:white_check_mark: Jira issue https://jira.corp.adobe.com/browse/AC-16194 is successfully created for this GitHub issue.

[m2-assistant[bot]]

:white_check_mark: Confirmed by @engcom-Hotel. Thank you for verifying the issue.
Issue Available: @engcom-Hotel, You will be automatically unassigned. Contributors/Maintainers can claim this issue to continue. To reclaim and continue work, reassign the ticket to yourself.