Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Hono | Hono | >= 4.12.0, < 4.12.2 |
Related Weaknesses (CWE)
References
- https://github.com/honojs/hono/commit/41adbf56e252c04611f8972364ac0887ae07a4c7Patch
- https://github.com/honojs/hono/releases/tag/v4.12.2ProductRelease Notes
- https://github.com/honojs/hono/security/advisories/GHSA-xh87-mx6m-69f3Vendor Advisory
FAQ
What is CVE-2026-27700?
CVE-2026-27700 is a vulnerability with a CVSS score of 8.2 (HIGH). 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 Ba...
How severe is CVE-2026-27700?
CVE-2026-27700 has been rated HIGH with a CVSS base score of 8.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-27700?
Check the references section above for vendor advisories and patch information. Affected products include: Hono Hono.