CVE-2026-27700 PUBLISHED

Hono is Vulnerable to Authentication Bypass by IP Spoofing in AWS Lambda ALB conninfo

Assigner: GitHub_M
Reserved: 23.02.2026 Published: 25.02.2026 Updated: 25.02.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
CVSS Score: 8.2

Product Status

Vendor honojs
Product hono
Versions
  • Version >= 4.12.0, < 4.12.2 is affected

References

Problem Types

  • CWE-345: Insufficient Verification of Data Authenticity CWE
  • CWE-290: Authentication Bypass by Spoofing CWE