One link causes critical error

Hi @sageth

I hope you’re well today and thank you for reporting this!

I tried to replicate this with various links on my end but to no luck. You mentioned it was on a single link only so I’m wondering if there was something specific about that link – like it’s location or format.

Is there anything additional about it that you could possibly share? For example, the link itself, where it is located on site (like e.g. on a standard post/page, on some custom post type or in some specific widget/block etc)?

Note: feel free to mask the domain and any “sensitive” info?

It would be helpful in understanding why this caused this error.

Best regards,
Adam

The only place that this link existed is on a Page (not Post) where I had a FAQ.

The link location went to the following location (redirect_to was left empty). /wp-login.php?action=register&redirect_to=

Functionally, this worked correctly in a browser. I don’t think that there was anything special with this other than that it redirected to a login page. However, the login/admin pages are locked behind a web page for authentication (Cloudflare Zero Trust) and isn’t a basic auth login with the pop-up asking for username/password.

This is a slightly different setup and I’m not discounting that as a cause.

Hi @sageth,

Thank you for further clarification.

As Cloudflare Zero Trust is an external tool, it shouldn’t be causing a Fatal error at the plugin end. However, I configured the login URL of a test website with Cloudflare Zero Trust but was unable to replicate the issue. Once Zero Trust was enabled, the login URL was listed as a redirecting URL in Broken Link Checker, however, the sub-section ‘Redirects’ was loading fine without any errors.

I suspect it was a temporary glitch on your website, as I couldn’t find any similar issues reported previously.

Could you please update us here if the issue reappears, so that we can take a closer look at it?

Kind Regards,
Nebu John

Once I did the temporary fix by commenting out that line, I was able to dismiss it and subsequently unlinked the URL as I no longer allow logins.

The error has not returned. I will post back here if I see it come up again. Thank you for researching.

Looks like I had missed a link, as it showed up again today in the “redirects” section of the plugin. In this case, the link goes to /wp-login.php?registration=disabled

It shows as a 200 and under source, it says:

There has been a critical error on this website. Please check your site admin email inbox for instructions.

Learn more about troubleshooting WordPress.

I am unable to interact with that row (or, in the case before, anything on that page). Following the link by manually typing it in brings me to a cloudflare zero trust error page.

I don’t know where this is coming from yet, as the source is showing the error. I will need to do more research.

Stack trace appears the same (some items edited):

2024/03/31 19:39:32 [error] 1014#1014: *5918 FastCGI sent in stderr: "PHP message: PHP Fatal error:  Uncaught ArgumentCountError: 3 arguments are required, 2 given in /var/html/wp-content/plugins/broken-link-checker/legacy/includes/any-post.php:579
Stack trace:
#0 /var/html/wp-content/plugins/broken-link-checker/legacy/includes/any-post.php(579): sprintf()
#1 /var/html/wp-content/plugins/broken-link-checker/legacy/includes/any-post.php(543): blcAnyPostContainer->get_edit_url()
#2 /var/html/wp-content/plugins/broken-link-checker/legacy/includes/instances.php(463): blcAnyPostContainer->ui_get_source()
#3 /var/html/wp-content/plugins/broken-link-checker/legacy/includes/admin/table-printer.php(798): blcLinkInstance->ui_get_source()
#4 /var/html/wp-content/plugins/broken-link-checker/legacy/includes/admin/table-printer.php(490): blcTablePrinter->column_used_in()
#5 /var/html/wp-content/plugins/broken-link-checker/legacy/includes/admin/table-printer.php(147): blcTablePrinter->link_row()
#6 /var/html/w" while reading upstream, client: xxx, server: xxx, request: "GET /wp-admin/admin.php?page=blc_local&filter_id=redirects HTTP/2.0", upstream: "fastcgi://unix:/var/run/php-fpm.sock:", host: "xxx", referrer: "https://example.com/wp-admin/admin.php?page=blc_local"

• This reply was modified 8 months ago by Sageth. Reason: clarifying

Hi @sageth

Thank you for getting back to us with additional information.

I’ve passed that all to our developers so they could analyze the case and related code and see if they can find explanation (and, hopefully, possible improvement/fix for future releases of the plugin) for this.

I’d appreciate some patience as they are dealing with a lot of complex tasks on daily basis so it may take them a while to check it all but I hope they’ll be able to shed some light on that – we’ll let you know once we got feedback.

Best regards,
Adam

Hi @sageth

Our developers after trying many times werestill not able to replicate this issue. If you can check in this function get_edit_url available in the file /wp-content/plugins/broken-link-checker/legacy/includes/any-post.php , what happens if you print $post, admin_url( sprintf( $post_type_object->_edit_link . $action, $post->ID ) ) and $post->ID

print_r($post);
echo admin_url( sprintf( $post_type_object->_edit_link . $action, $post->ID ) );
echo $post->ID;

Also, what happens if you just use a return admin_url( sprintf( $post_type_object->_edit_link . $action, $post->ID ) ) instead of this apply_filters( 'get_edit_post_link', admin_url( sprintf( $post_type_object->_edit_link . $action, $post->ID ) ), $post->ID, $context )

Kind Regards,
Kris

The first block printed fine, though I get the error still. I see the post contents and the ID, so I can identify the specific page now, however, I still get the wordpress error. I substantially cut this data down and only copied a bit of the post:

WP_Post Object ( [ID] => 15235 [post_author] => 1 [post_date] => 2023-11-10 14:32:11 [post_date_gmt] => 2023-11-10 19:32:11 [post_content] =>

Our Latest Posts

No posts were found.

WP_Post Object ( [ID] => 15235 [post_author] => 1 [post_date] => 2023-11-10 14:32:11 [post_date_gmt] => 2023-11-10 19:32:11 [post_content] => [post_title] => Blog Home [post_excerpt] => Displays the latest posts as either the site homepage or as the “Posts page” as defined under reading settings. If it exists, the Front Page template overrides this template when posts are shown on the homepage. [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => home [to_ping] => [pinged] => [post_modified] => 2024-04-09 19:48:45 [post_modified_gmt] => 2024-04-09 23:48:45 [post_content_filtered] => [post_parent] => 0 [guid] => https://example.com/uncategorized/home [menu_order] => 0 [post_type] => wp_template [post_mime_type] => [comment_count] => 0 [filter] => raw )

There has been a critical error on this website. Please check your site admin email inbox for instructions.

Learn more about troubleshooting WordPress.

For the second, I tried removing the filter and it made no difference.

Over the weekend, I had also tried debugging further and dumping $this and $post, but nothing stuck out as particularly interesting. Whatever happens on this link, though, it prevents all other BLC links on the page from working.

My link https://example.com/wp-login.php?registration=disabled redirects to this Cloudflare product (https://www.cloudflare.com/zero-trust/products/access/). Anything that goes to wp-login.php* will redirect to a sort of an MFA page off-domain. That page is publicly accessible from everywhere and, once passing the MFA, will redirect to the correct location. The URL format is like this:

https://myalias.cloudflareaccess.com/cdn-cgi/access/login/example.com?blah=…

I have verified with curl that it returns a 200 after a 301 redirect.

Last, I enabled email debugging and the email seems to have a longer stack trace (which I haven’t looked into too deeply yet). Ultimately, I don’t know why this fails the way that it does — I have a lot of other external links with redirects

Error Details
=============
An error of type E_ERROR was caused in line 579 of the file /var/html/wp-content/plugins/broken-link-checker/legacy/includes/any-post.php. Error message: Uncaught ArgumentCountError: 3 arguments are required, 2 given in /var/html/wp-content/plugins/broken-link-checker/legacy/includes/any-post.php:579
Stack trace:
#0 /var/html/wp-content/plugins/broken-link-checker/legacy/includes/any-post.php(579): sprintf()
#1 /var/html/wp-content/plugins/broken-link-checker/legacy/includes/any-post.php(543): blcAnyPostContainer->get_edit_url()
#2 /var/html/wp-content/plugins/broken-link-checker/legacy/includes/instances.php(463): blcAnyPostContainer->ui_get_source()
#3 /var/html/wp-content/plugins/broken-link-checker/legacy/includes/admin/table-printer.php(798): blcLinkInstance->ui_get_source()
#4 /var/html/wp-content/plugins/broken-link-checker/legacy/includes/admin/table-printer.php(490): blcTablePrinter->column_used_in()
#5 /var/html/wp-content/plugins/broken-link-checker/legacy/includes/admin/table-printer.php(147): blcTablePrinter->link_row()
#6 /var/html/wp-content/plugins/broken-link-checker/legacy/core/core.php(1988): blcTablePrinter->print_table()
#7 /var/html/wp-content/plugins/broken-link-checker/app/admin-pages/local-submenu/class-view.php(52): wsBrokenLinkChecker->links_page()
#8 /var/html/wp-content/plugins/broken-link-checker/app/admin-pages/local-submenu/class-controller.php(189): WPMUDEV_BLC\App\Admin_Pages\Local_Submenu\View->render()
#9 /var/html/wp-includes/class-wp-hook.php(324): WPMUDEV_BLC\App\Admin_Pages\Local_Submenu\Controller->output()
#10 /var/html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters()
#11 /var/html/wp-includes/plugin.php(517): WP_Hook->do_action()
#12 /var/html/wp-admin/admin.php(259): do_action()
#13 {main}
 thrown

Just because the post above is so large already, I commented out printing the source in table-printer again and I ran the URL check. Here’s what I see (again, nothing special to me):

Link last checked: April 10, 2024
HTTP code: 200
Response time: 0.128 seconds
Final URL: https://myalias.cloudflareaccess.com/cdn-cgi/access/login/example.com?kid=8a5d7b96f37ab8554732060a5925144cd879dcad13a6f17d989bfca07ebd985a&redirect_url=%2Fwp-login.php%3Fregistration%3Ddisabled&meta=3N1ZXJaaw
Redirect count: 1
Instance count: 1

Log shows:

Log: === HTTP code : 200 ===

Response headers
================
HTTP/2 302
date: Wed, 10 Apr 2024 01:34:22 GMT
location: https://myalias.cloudflareaccess.com/cdn-cgi/access/login/example.com?kid=8a5d7b96f37ab8554732060a5925144cd879dcad13a6f17d989bfca07ebd985a&redirect_url=%2Fwp-login.php%3Fregistration%3Ddisabled&meta=3N1ZXJaaw
set-cookie: CF_AppSession=abc123; Expires=Thu, 11 Apr 2024 01:34:22 GMT; Path=/; Secure; HttpOnly
access-control-allow-credentials: true
cache-control: private, max-age=0, no-store, no-cache, must-revalidate, post-check=0, pre-check=0
expires: Thu, 01 Jan 1970 00:00:01 GMT
report-to: {"endpoints":[{"url":"https:\/\/a.nel.cloudflare.com\/report\/v4?s=utKctBn0xYlt"}],"group":"cf-nel","max_age":604800}
nel: {"success_fraction":0,"report_to":"cf-nel","max_age":604800}
strict-transport-security: max-age=31536000; includeSubDomains; preload
expect-ct: max-age=86400, enforce
referrer-policy: same-origin
x-content-type-options: nosniff
x-frame-options: SAMEORIGIN
x-xss-protection: 1; mode=block
server: cloudflare
cf-ray: 871efe7bbd2e6a5f-EWR
alt-svc: h3=":443"; ma=86400

HTTP/2 200
date: Wed, 10 Apr 2024 01:34:22 GMT
content-type: text/html
content-length: 28387
access-control-allow-origin: null
set-cookie: CF_Session=nZkCXs6ZewQkrxpGG; Path=/; Secure; Expires=Wed, 10 Apr 2024 05:34:22 GMT; HttpOnly; SameSite=none
strict-transport-security: max-age=31536000; includeSubDomains
access-control-allow-credentials: true
cf-access-domain: example.com
cf-version: 1651-0fbc2fc
content-security-policy: frame-ancestors 'none'; connect-src 'self' https://127.0.0.1:*; default-src https: 'unsafe-inline'
referrer-policy: strict-origin-when-cross-origin
x-content-type-options: nosniff
x-frame-options: DENY
x-xss-protection: 1; mode=block
server: cloudflare
cf-ray: 871efe7bd90143f4-EWR

Request headers
================
GET /cdn-cgi/access/login/example.com?kid=abcd&redirect_url=%2Fwp-login.php%3Fregistration%3Ddisabled&meta=3N1ZXJaaw HTTP/2
Host: myalias.cloudflareaccess.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.5112.34 Safari/537.36
Accept: */*
Referer: https://example.com
Connection: close
Range: bytes=0-2048


Link is valid.

I’m willing to give the exact URL which causes the issue so you can see how it behaves, but I would prefer not to post my URL here. Is there somewhere I can provide a few private details while we troubleshoot more publicly?

Hi @sageth

Please email us at: [email protected]
Subject: ATTN: WPMU DEV support – wp.org

Please send:
– Link back to this thread for reference (https://www.ads-software.com/support/topic/one-link-causes-critical-error/)
so that we could review this case more for you

Kind Regards,
Kris

Hi @sageth,

We haven’t heard from you in a while, I’ll go and mark this thread as resolved. Note that you can still reply on this topic.

If you have any additional questions or require further help, please let us know!

Best regards,
Laura