What’s Vulnerable › Vulnerabilities

CVE-2026-69211: Http4s: Set-Cookie rendering does not escape attribute delimiters

• Severity: medium (CVSS 4.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-15 · updated 2026-09-16
• Weakness: CWE-113

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

• http4s: before 0.23.35; from 1.0.0-M1, < 1.0.0-M47

References

• https://github.com/http4s/http4s/commit/5c8e69ac0f4a2fe03c3481dccd74101cd2e2a890
• https://github.com/http4s/http4s/releases/tag/v0.23.35
• https://github.com/http4s/http4s/releases/tag/v1.0.0-M47
• https://github.com/http4s/http4s/security/advisories/GHSA-7qh7-rghh-698h

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