This was an error found by @metamania01 of the Audit Company Solshield.
It allowed one to verify a creator that did not sign by making use of a provision in Token Metadata that allows Creators who have signed compressed nfts to allow them to decompress with verified creators.
The issue is now patched.
For more info see.
https://twitter.com/thehasheddude/status/1601642138143375360
References
- https://github.com/metaplex-foundation/metaplex-program-library/security/advisories/GHSA-8r76-fr72-j32w
- https://github.com/metaplex-foundation/metaplex-program-library/commit/c18591a7ce9bb561940cb94df4b7c35ef9cc0f57
- https://twitter.com/thehasheddude/status/1601642138143375360
- https://github.com/advisories/GHSA-8r76-fr72-j32w