CVE-2026-47675

Hono: Cookie helper does not sanitize sameSite and priority, allowing Set-Cookie injection

State: Published
Severity: 4.3 Medium
Published: May 28, 2026
Updated: May 28, 2026
Reserved: May 19, 2026

Description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, the serialize() function in hono/cookie validates domain and path options against characters that corrupt Set-Cookie header syntax (;, \r, \n), but does not apply the same validation to sameSite and priority. An application that passes user-controlled input into either option may produce a Set-Cookie response header containing attacker-chosen additional attributes. This vulnerability is fixed in 4.12.21.

Scores

CVSS	Score	Vector	Source
3.1	4.3 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N	GitHub_M

Weaknesses

CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
CWE-1287 Improper Validation of Specified Type of Input

Affected Products

Product	Versions
honohonojs	< 4.12.21Affected

References

https://github.com/honojs/hono/security/advisories/GHSA-3hrh-pfw6-9m5x

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