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Http4s: Set-Cookie rendering does not escape attribute delimiters

Published Sep 15, 2026

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

Remediation

No remediation recorded yet.

Weaknesses (2)

References (5)

Change history (0)

No recorded changes yet.

Sources
CVE.org / MITRE
Status PUBLISHED
Assigner GitHub_M
Published Sep 15, 2026
Updated Sep 16, 2026
Reserved Aug 3, 2026
CISA Vulnrichment
Updated Sep 16, 2026
NVD
Status Deferred
Modified Sep 16, 2026
Red Hat
Severity n/a
Public date n/a
ENISA EUVD
Assigner GitHub_M
Published Sep 15, 2026
Updated Sep 16, 2026
Exploited since n/a
EUVD-2026-79175