What’s Vulnerable › Vulnerabilities

CVE-2026-29086: Hono: Cookie Attribute Injection via Unsanitized domain and path in setCookie()

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-04 · updated 2026-06-17
• Weakness: CWE-1113

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.

Affected products

• honojs hono: before 4.12.4 — fixed in 4.12.4

How to fix

Upgrade to a fixed version: honojs hono 4.12.4. Check the vendor advisory for mitigations.

References

• https://github.com/honojs/hono/commit/44ae0c8cc4d5ab2bed529127a4ac72e1483ad073
• https://github.com/honojs/hono/security/advisories/GHSA-5pq2-9x2x-5p6w

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