Skip to content
OpenAdvisories
Medium · 4.8 CVE-2026-69211 EUVD-2026-79175

Http4s: Set-Cookie rendering does not escape attribute delimiters

Published Sep 15, 2026 · Updated Sep 16, 2026 · Assigned by GitHub_M

Description

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, ResponseCookie.render writes attacker-influenced name, content, domain, path, and extension values without neutralizing semicolons or control characters. An application that constructs a ResponseCookie from unvalidated input can therefore emit injected cookie attributes such as Domain, Path, or SameSite, widening cookie scope or weakening protections, and control characters may enable header splitting on permissive backends. The patch strips control characters from all five fields and strips semicolons from name, content, domain, and path while retaining the extension delimiter behavior. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

Affected products

VendorProductAffectedFixed
http4s http4s < 0.23.35, >= 1.0.0-M1, < 1.0.0-M47 —

References