CVE-2026-69215: HTTP4S

Medium severity, CVSS 6.8. EPSS: 0.5% chance of exploitation in the next 30 days.

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The CookieJar client middleware uses unanchored substring checks instead of RFC 6265 domain and path matching when deciding whether to attach a stored cookie. A cookie for example.com can consequently be sent to an attacker-controlled hostname such as evilexample.com when an application using the same jar makes an attacker-influenced outbound request. This exposes session or authentication cookies and can enable hijacking of the application’s outbound sessions. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

Affected products

• HTTP4S HTTP4S: before 0.23.35 (fixed in 0.23.35); from 1.0.0-M1, before 1.0.0-M47 (fixed in 1.0.0-M47)

Published 2026-09-15. Last modified 2026-09-16.