HTTP response splitting in hono - CVE-2026-29086
Published: July 24, 2026
Vulnerability identifier: #VU139312
CSH Severity: Medium
CVSS v4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-29086
CWE-ID: CWE-113
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to manipulate cookie attributes.
The vulnerability exists due to improper neutralization of CRLF sequences in HTTP headers in the setCookie() utility when constructing the Set-Cookie header using untrusted domain or path option values. A remote attacker can supply crafted input containing semicolons, carriage returns, or newline characters to manipulate cookie attributes.
User interaction is required, and exploitation depends on an application passing user-controlled input directly into the domain or path options.
Affected software
hono
How to mitigate CVE-2026-29086
Install security update from vendor's website.
hono - update to 4.12.4