The provided commit diff (a8775aa) only modifies the README.md file and does not show code changes related to the vulnerability. The actual patched code changes are not included in the provided data, making it impossible to identify specific vulnerable functions with high confidence. Code injection vulnerabilities in Ruby often involve unsafe input handling (e.g., eval, system calls), but without seeing the pre-patch implementation details or security-focused diffs, we cannot definitively pinpoint the affected functions. The advisory descriptions confirm the vulnerability exists in processing crafted requests but lack technical specifics about the flawed code paths.