Input validation error in hono - CVE-2026-39410
Published: July 24, 2026
Vulnerability identifier: #VU139306
CSH Severity: Medium
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-39410
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to override sensitive cookies.
The vulnerability exists due to improper input validation in getCookie() cookie parsing when handling cookie names with a non-breaking space prefix. A remote attacker can set a specially crafted cookie to override sensitive cookies.
This issue affects applications that rely on getCookie() for security-sensitive cookie handling and may enable bypass of __Secure- and __Host- prefix protections.
Affected software
hono
How to mitigate CVE-2026-39410
Install security update from vendor's website.
hono - update to 4.12.12