CVE-2026-29086
Cookie Injection Vulnerability in Hono setCookie() Utility
Publication date: 2026-03-04
Last updated on: 2026-03-06
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| hono | hono | to 4.12.4 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-1113 | The source code uses comment styles or formats that are inconsistent or do not follow expected standards for the product. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
The vulnerability exists in the Hono web application framework prior to version 4.12.4, specifically in the setCookie() utility. This utility did not properly 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 separated by semicolons, an attacker could inject additional cookie attributes if untrusted input was passed into these fields, potentially manipulating cookie behavior.
This issue was fixed in version 4.12.4 of Hono.
How can this vulnerability impact me? :
This vulnerability can lead to injection of additional cookie attributes by an attacker if untrusted input is passed into the domain or path options of the setCookie() utility.
Such injection could alter cookie behavior, potentially affecting the security and integrity of user sessions or data handled by the application.
The CVSS score of 5.4 indicates a moderate severity with potential impacts on confidentiality and integrity, but no impact on availability.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, upgrade the Hono Web application framework to version 4.12.4 or later, where the issue with setCookie() utility has been patched.