HTTP response splitting in hono - CVE-2026-47675
Published: July 24, 2026
Vulnerability identifier: #VU139279
CSH Severity: Low
CVSS v4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-47675
CWE-ID: CWE-113
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to inject additional attributes into a Set-Cookie response header.
The vulnerability exists due to improper neutralization of CRLF sequences in HTTP headers and improper input validation in the serialize() function in hono/cookie when processing user-controlled sameSite or priority option values. A remote attacker can supply a crafted option value to inject additional attributes into a Set-Cookie response header.
User interaction is required because exploitation occurs when an application passes user-controlled input to the sameSite or priority option of setCookie() or serialize().
Affected software
hono
How to mitigate CVE-2026-47675
Install security update from vendor's website.
hono - update to 4.12.21