AES-CBC without PKCS#7 padding for 16-byte aligned blocks

It looks like the current implementations in Chrome (95) and Safari (15) add 16 bytes of padding to already 16-byte aligned blocks prior to encryption (and expect the same when decrypting), and it appears to be correct according to the WebCrypto spec and https://datatracker.ietf.org/doc/html/rfc2315#section-10.3 it is referring.

However this is not compatible with ISO/IEC 23001-7 spec (aka Common Encryption) which doesn't allow any sort of padding whatsoever, all the AES-CBC operations are performed on blocks of size multiple of 16 bytes ("tail" bytes are passed unencrypted). The problem is that ISO/IEC 23001-7 is the base of all the DRM protection frameworks these days and AES-CBC is the only mode which makes Apple, Google, MS and DRM hardware vendors happy at the same time - it answers the question "what's the use case?":
https://lists.w3.org/Archives/Public/public-webcrypto-comments/2014Jun/0006.html

Btw WebCrypto's AES-CTR is fully compatible with ISO/IEC 23001-7, I was able to decrypt DRM-protected data with WebCrypto as long as it was AES-CTR, but handling CBC in a compatible way is plain impossible at the moment.

Start with the WebCrypto specification's AES-CBC behavior and the linked RFC 2315 and ISO/IEC 23001-7 references. Compare their padding requirements and determine what API or specification change could provide compatibility; done means an agreed resolution for CBC handling.