"Missing feature Cookies" and content blocked when accessed though an iframe in Safari

[serasset]

Describe the bug

Hi,

I am accessing a specific web page: https://haltools.archives-ouvertes.fr/Public/afficheRequetePubli.php?projet_anr=ANR-23-IAS1-0001&CB_auteur=oui&CB_titre=oui&CB_article=oui&langue=Anglais&tri_exp=annee_publi&tri_exp2=typdoc&tri_exp3=date_publi&ordre_aff=TA&Fen=Aff&css=../css/styles_publicationsHAL.css

• When directly accessed on Safari (Version 26.2 (20623.1.14.18.4)) on a Mac, I get the resulting page.
• When accessed through another webpage hosting it in an iframe (https://pantagruel.imag.fr/papers/)
  • It works with Chrome and Firefox
  • It fails on Safari with a "Missing feature Cookies" error

Reproduced on MacOS and iOS, so it seems to be a Safari issue.

Extensions:

• Ghostery (disactivating it on the pantagruel.imag.fr website does not solve the problem
• Raindrop.io
• Zotero

I contacted the haltools.archives-ouvertes.fr ones to no avail yet,

Any idea to help me/them fix the problem ?

Thx

Steps to reproduce

1. Go to https://pantagruel.imag.fr/papers/ using a pretty recent Safari
2. The embedded website will give an error

Expected behavior

Your operating system and its version.

macOS / OS X 10.15.7

Your browser and its version.

Safari 26

Additional context

No response

[ciencia]

[disclaimer: I'm not an anubis developer]
This seems to be a "feature" from Safari. If you search for Safari cookies iframe on your favorite search engine, you'll see a lot of pages describing that issue.

It doesn't seem possible to overcome this problem according to this SO question.