CVE-2026-34975

EIP tracks 1 public exploit for CVE-2026-34975. PoCs published by romain-deperne.

AI-analyzed exploit summary This repository contains a functional exploit PoC for CVE-2026-34975, demonstrating CRLF injection in Plunk's email header construction. The PoC includes detailed technical analysis and multiple injection vectors (from.name, subject, custom headers, attachment filenames) to inject arbitrary email headers, such as Bcc, enabling silent email redirection.

Plunk is an open-source email platform built on top of AWS SES. Prior to 0.8.0, a CRLF header injection vulnerability was discovered in SESService.ts, where user-supplied values for from.name, subject, custom header keys/values, and attachment filenames were interpolated directly into raw MIME messages without sanitization. An authenticated API user could inject arbitrary email headers (e.g. Bcc, Reply-To) by embedding carriage return/line feed characters in these fields, enabling silent email forwarding, reply redirection, or sender spoofing. The fix adds input validation at the schema level to reject any of these fields containing \r or \n characters, consistent with the existing validation already applied to the contentId field. This vulnerability is fixed in 0.8.0.