Medium severity · published Mar 4, 2026
CVE-2026-29086
Hono: Cookie Attribute Injection via Unsanitized domain and path in setCookie()
5.4
CVSS
0.2%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 14% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
HO
hono · honojs
< 4.12.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-29086
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-29086
Patch
https://github.com/honojs/hono/commit/44ae0c8cc4d5ab2bed529127a4ac72e1483ad073
Vendor Advisory
https://github.com/honojs/hono/security/advisories/GHSA-5pq2-9x2x-5p6w
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