GHSA-4jgr-pg2m-m988: Heimdall: Forwarded Header Injection via Unsanitized Host Header in Proxy Mode

When Heimdall operates in proxy mode, it constructs the Forwarded HTTP header after executing the matched rule pipeline by inserting the incoming request’s Host header value directly into the header string without sanitizing commas or semicolons. This allows an attacker to inject additional parameters into the Forwarded header, potentially spoofing IP addresses for upstream services.