GHSA-gcjf-9mgh-3p7g: Netty: CRLF Injection via Multipart Filename in Netty HttpPostRequestEncoder

Security Vulnerability Report: CRLF Injection via Multipart Filename in Netty HttpPostRequestEncoder 1. Vulnerability Summary | Field | Value | |-------|-------| | Product | Netty | | Version | 4.2.12.Final (and all prior versions with codec-http multipart) | | Component | io.netty.handler.codec.http.multipart.HttpPostRequestEncoder | | Vulnerability Type | CWE-93: Improper Neutralization of CRLF Sequences / CWE-113: HTTP Response Splitting | | Impact | MIME Header Injection / Content-Type Spoofing / XSS via Content-Disposition | | CVSS 3.1 Score | 8.1 (High) | | CVSS 3.1 Vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N | | Attack Vector | Network | | Attack Complexity | Low | | Privileges Required | Low (attacker must be able to upload files with controlled filenames) | | User Interaction | None | | Scope | Unchanged | | Confidentiality Impact | High | | Integrity Impact | High | | Availability Impact | None | 2. Affected Components The following classes in the codec-http module are affected: - io.netty.handler.codec.http.multipart.HttpPostRequestEncoder — directly concatenates unvalidated filename/name into Content-Disposition MIME headers (lines 519, 633, 674, 682, 686-688) - io.netty.handler.codec.http.multipart.DiskFileUpload — setFilename() only checks null (line 78) - io.netty.handler.codec.http.multipart.MemoryFileUpload — setFilename() only checks null (line 60) - io.netty.handler.codec.http.multipart.MixedFileUpload — setFilename() delegates without validation (line 62) 3. Vulnerability Description Netty's HttpPostRequestEncoder constructs multipart HTTP request bodies by directly concatenating user-supplied filenames and field names into Content-Disposition MIME headers without validating or sanitizing CRLF characters (\r\n). Since MIME headers are delimited by CRLF, an attacker who controls the filename can inject arbitrary MIME headers into the multipart body part. Root Cause In HttpPostRequestEncoder.java, multiple code paths directly emb