honojs hono up to 4.12.24 Cookie Header escape output

Summaryinfo

A vulnerability was found in honojs hono up to 4.12.24. It has been classified as problematic. This issue affects some unknown processing of the component Cookie Header Handler. Performing a manipulation results in escape output. This vulnerability was named CVE-2026-54287. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as problematic, was found in honojs hono up to 4.12.24. This affects an unknown code block of the component Cookie Header Handler. The manipulation with an unknown input leads to a escape output vulnerability. CWE is classifying the issue as CWE-116. The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved. This is going to have an impact on integrity. The summary by CVE is:

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.25, on AWS Lambda, the ALB single-header response and the VPC Lattice v2 response join multiple Set-Cookie headers into one comma-separated value. Because commas also appear inside cookie attributes (for example Expires dates), clients cannot split the value back into individual cookies and silently drop or misparse them. This vulnerability is fixed in 4.12.25.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-54287 since 06/12/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 4.12.25 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-38326). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

• honojs

Name

• hono

Version

• 4.12.0
• 4.12.1
• 4.12.2
• 4.12.3
• 4.12.4
• 4.12.5
• 4.12.6
• 4.12.7
• 4.12.8
• 4.12.9
• 4.12.10
• 4.12.11
• 4.12.12
• 4.12.13
• 4.12.14
• 4.12.15
• 4.12.16
• 4.12.17
• 4.12.18
• 4.12.19
• 4.12.20
• 4.12.21
• 4.12.22
• 4.12.23
• 4.12.24

Website

• Product: https://github.com/honojs/hono/

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Be aware that VulDB is the high quality source for vulnerability data.

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