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8.2 High

CVE-2026-27700 Hono is a Web application framework that provides support for any JavaScript runtime

Description

Hono is a Web application framework that provides support for any JavaScript runtime. In versions 4.12.0 and 4.12.1, when using the AWS Lambda adapter (`hono/aws-lambda`) behind an Application Load Balancer (ALB), the `getConnInfo()` function incorrectly selected the first value from the `X-Forwarded-For` header. Because AWS ALB appends the real client IP address to the end of the `X-Forwarded-For` header, the first value can be attacker-controlled. This could allow IP-based access control mechanisms (such as the `ipRestriction` middleware) to be bypassed. Version 4.12.2 patches the issue.

Affected products and versions

Product Affected versions Fixed in
hono 4.12 4.12.0 → < 4.12.2 4.12.2
The 48 CVEs of hono →
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