CVE-2026-56762

MEDIUM EPSS 15.8%
Published Jun 23, 20261w ago · Modified Jun 24, 20266d ago
6.9 CVSS 4.0
Medium
Find Similar
Published Jun 23, 2026 1w ago
Last Modified Jun 24, 2026 6d ago

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 Details

Base Score
6.9
Exploitability
Impact
Vector string
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
15.8% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-20 Improper Input Validation Validation

References 2

  • github.com https://github.com/honojs/hono/security/advisories/GHSA-26pp-8wgv-hjvm
  • vulncheck.com https://www.vulncheck.com/advisories/hono-missing-cookie-name-validation-in-setcookie

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.