Vulnerability Description
Hono before 4.12.12 does not validate cookie names on the write path in the setCookie(), serialize(), and serializeSigned() functions, allowing invalid characters such as control characters (e.g. \r or \n) when an application passes a user-controlled cookie name. This can produce malformed Set-Cookie header values. In modern runtimes such as Node.js and Cloudflare Workers, such invalid header values are rejected and cause a runtime error before the response is sent, so header injection or response splitting could not be reproduced; the issue primarily affects correctness and robustness, resulting in runtime errors (availability) rather than confirmed header injection.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/honojs/hono/security/advisories/GHSA-26pp-8wgv-hjvm
- https://www.vulncheck.com/advisories/hono-missing-cookie-name-validation-in-setc
FAQ
What is CVE-2026-56762?
CVE-2026-56762 is a vulnerability with a CVSS score of 5.3 (MEDIUM). Hono before 4.12.12 does not validate cookie names on the write path in the setCookie(), serialize(), and serializeSigned() functions, allowing invalid characters such as control characters (e.g. \r o...
How severe is CVE-2026-56762?
CVE-2026-56762 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-56762?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.