CVE-2022-42975: 
Homebrew vulnerability analysis and mitigation

socket/transport.ex in Phoenix before 1.6.14 contains a vulnerability in the wildcard check_origin functionality. The vulnerability allows attackers to bypass origin checks by registering a domain with a custom prefix of a target domain (Phoenix Commit).

The vulnerability exists in the comparison logic for wildcard checkorigin patterns like "//*.other.com". The flawed implementation would incorrectly allow domains like api.any-other.com to pass origin checks, instead of properly restricting to only subdomains of the specified domain. The issue stems from insufficient validation of the subdomain dot prefix in the String.endswith? check (Phoenix Commit).

The impact is limited to applications using wildcard check_origin configurations. The vulnerability allows unauthenticated channel connections from unauthorized hosts. However, LiveView applications are unaffected by default due to the presence of CSRF tokens. Additionally, channels using token-based authentication would still require valid tokens, and the vulnerability does not allow access to cookies (Phoenix Commit).

The vulnerability was fixed in Phoenix version 1.6.14 by modifying the wildcard comparison logic to properly validate the subdomain dot prefix. The patch ensures String.ends_with? check includes the proper domain validation (Phoenix Commit).