Vulnerability in Hono
CVE-2026-29086
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to version 4.12.4, the setCookie() utility did not validate semicolons (;), carriage returns (\r), or newline characters (\n) in the domain and path options when constructing the Set-Cookie header. Because cookie attributes are delimited by semicolons, this could allow injection of additional cookie attributes if untrusted input was passed into these fields. This issue has been patched in version 4.12.4.
EPSS: 0.002 (11.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.
Affected products
- Hono
- Honojs Hono — versions < 4.12.4
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-29086?
- CVE-2026-29086 is a medium-severity vulnerability in Hono, classified under CWE-1113. CVSS score: 5.4/10. Published 2026-03-04.
- How severe is CVE-2026-29086?
- Medium severity. CVSS v3 base score is 5.4 out of 10.