css.properties.background-attachment - `background-attachment:fixed` is not supported in iOS Safari

[mmkthecoolest]

What type of issue is this?

Incorrect support data (example: BrowserX says "86" but support was added in "40")

What information was incorrect, unhelpful, or incomplete?

On the compatibility table for background-attachment, it says that the fixed value is supported on Safari for iOS, which in my opinion is actually incorrect. The table says that this was fixed in Safari for iOS 15.4, but the bug report cited only refers to background-attachment: local behavior on Safari for macOS. There is an open bug report regarding this feature not working, and I can confirm that this is still an issue as of iOS 26.

Furthermore, from what I am seeing, a WebKit developer has stated that background-attachment: fixed is not supported on iOS, and at one point another WebKit developer made a pull request to set @supports(background-attachment:fixed) as false for iOS web browsers (however, this PR was closed by its author a few months ago, despite the originating bug report still being open).

What browsers does this problem apply to, if applicable?

Safari

What did you expect to see?

I expect to see support for background-attachment: fixed as false for Safari on iOS in the compatibility table.

Did you test this? If so, how?

It can be verified on this link. The background will remain fixed while scrolling on all browsers except Safari on iOS/iPadOS since this page makes use of background-attachment: fixed.

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

• MDN page containing incorrect information about background-attachment: fixed compatibility for iOS
• WebKit developer confirming lack of support for background-attachment: fixed on iOS
• Bug report suggesting to set @supports(background-attachment: fixed) to false on iOS

Do you have anything more you want to share?

No response

MDN URL

https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Properties/background-attachment

MDN metadata

MDN page report details

• Query: css.properties.background-attachment
• Report started: 2026-01-11T07:56:56.140Z

[caugner]

Good catch, it looks like this was introduced in #18507. The Safari notes for fixed originally mentioned local, which was only fixed for Safari iOS in #12463, and this may have caused the confusion.

I will open a PR to fix.

[caugner]

Verified via BrowserStack Live that this interactive example (mentioned in bug 275247) works in Safari 15.6.1, but doesn't work in Safari for iOS 15.4 or 26.2.