Bug 315895 – REGRESSION (iOS 26.5): Loading an iframe of Notion page causes a crash

• Component: New Bugs
• Status: RESOLVED DUPLICATE

# Overview

The specific page displays fine on iOS 26.4 or earlier versions, but the browser crashed on iOS 26.5.

"The specific page" refers to an HTML page that loads a Notion page via an iframe.

I'm not sure if this issue is caused by Notion's JavaScript implementation or by iOS 26.5, but I have confirmed that the problem occurs on iOS 26.5.

# Steps to Reproduce

Create a simple HTML page. Include the following iframe code.

<iframe src="https://_.notion.site/ebd/" width="400" height="400"></iframe>

When you open the page in Safari or Google Chrome on iOS 26.5, an error message stating "A problem repeatedly occurred on (URL)" appears and the browser crashes.

# Additional Information

No problems will occur if you access the URL directly rather than via an iframe.

I did not encounter the problem with the Firefox browser on iOS 26.5.

# Note

Public pages created in Notion have URLs that look like this.

https://USERNAME.notion.site/PAGEHASH

To embed this page into any HTML page using an iframe, you can use a URL with /ebd/ (embed) appended as shown below.

https://USERNAME.notion.site/ebd/PAGEHASH

The Notion embed URL used in the sample code is a dummy URL for a page that does not exist.

https://_.notion.site/ebd/

# Background

This report was prompted by reports from some users that they were unable to view a plain HTML page that actually embeds a Notion page via an iframe.

After investigating the issue, we found that it appears to be occurring only among iPhone users running iOS 26.5.

Users of iOS 26.4.2 have reported that they have not encountered any issues. Furthermore, when I tested it myself, I did not encounter any issues on iOS 26.0.

The minimal code that reproduced the issue involved displaying the Notion page mentioned above in an iframe, but even after investigating the behavior of the Notion page’s JavaScript and the browser’s network activity, I was unable to identify a more direct cause.

[Alexey Proskuryakov]

Created attachment 479927 [details]
test case

[Alexey Proskuryakov]

Thank you for the report! I added an attachment with your example, and I cannot reproduce a crash with it. I'm on a newer build that's close to 26.6 beta though, so there is a chance that the issue was already fixed.

Could you please confirm whether this reproduces with the above attachment for you, and attach an .ips crash report? Here are the instructions <https://developer.apple.com/documentation/xcode/acquiring-crash-reports-and-diagnostic-logs>, usually the easiest way is via the Analytics & Improvements section of Settings on the device.

Created attachment 479934 [details]
Video recording in Safari on iOS 26.5

When I viewed that test case in Safari on my iPhone 12 mini running iOS 26.5, the problem was reproduced.

To analyze the problem, I attempted to capture the error logs. The three types of logs I focused on are as follows.

(L1) Console log on iOS Safari Web Inspector (Safari Developer tools).
(L2) The .ips format crash report file you mentioned.
(L3) Log messages from connected iPhone devices that can be viewed in the Console app on macOS.

There were no meaningful log messages for (L1).
I also attempted to capture logs for (L2), but even when I reproduced the problem in the browser, no IPS logs were generated.
I found the only log message from (L3) that seems relevant. It's a log with the message type "Faults".

Message-1:
```
/Library/Caches/com.apple.xbs/21FB6719-CFA0-477E-99A4-BC279D9CC831/TemporaryDirectory.SUqZVe/Sources/WebKit/Source/WebKit/UIProcess/WebLockRegistryProxy.cpp 63: Invalid message dispatched void WebKit::WebLockRegistryProxy::requestLock(WebCore::ClientOrigin &&, WebCore::WebLockIdentifier, WebCore::ScriptExecutionContextIdentifier, String &&, WebCore::WebLockMode, bool, bool)
```

Message-2:
```
Received an invalid message 'WebLockRegistryProxy_RequestLock' from the WebContent process with PID 632
```

These two pairs of log messages were output four times in a row. In the video below, you can see the page reloading, but it appears the browser crashed after attempting to reload the page a total of four times.
https://bug-315895-attachments.webkit.org/attachment.cgi?id=479934

Please let me know if there are any other items that need to be investigated.

[Alexey Proskuryakov]

Thank you. Looks like this got fixed as part of bug 314863 (I'm also checking with folks who worked on it to have some more eyes for confirmation).

This fix is available in the first beta of iOS 26.6.

*** This bug has been marked as a duplicate of bug 314863 ***

Thank you. It seems that existing issue is the cause. It looks like the commit details for that issue haven’t been published to the public repository yet.
https://results.webkit.org/commits

I’d like to check it out once information regarding the cause of this bug in iOS 26.5 and the fix details are made public.