GHSA-hh82-3pmq-7frp

### Impact When calling `DefaultHttpHeaders.set` with an _iterator_ of values (as opposed to a single given value), header value validation was not performed, allowing malicious header values in the iterator to perform [HTTP Response Splitting](https://owasp.org/www-community/attacks/HTTP_Response_Splitting). ### Patches The necessary validation was added in Netty 4.1.86.Final. ### Workarounds Integrators can work around the issue by changing the `DefaultHttpHeaders.set(CharSequence, Iterator<?>)` call, into a `remove()` call, and call `add()` in a loop over the iterator of values. ### References [HTTP Response Splitting](https://owasp.org/www-community/attacks/HTTP_Response_Splitting) [CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers](https://cwe.mitre.org/data/definitions/113.html) ### For more information If you have any questions or comments about this advisory: * Open an issue in [[example link to repo](https://github.com/netty/netty)](https://github.com/netty/netty) * Email us at [[email protected]](mailto:[email protected])