{"cve":"CVE-2026-27700","nvd":{"published":"2026-02-25T16:23:26.440","modified":"2026-06-17T10:27:32.397","status":"Analyzed","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_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","score":7.5},"cwes":["CWE-290","CWE-345"],"references":["https://github.com/honojs/hono/commit/41adbf56e252c04611f8972364ac0887ae07a4c7","https://github.com/honojs/hono/releases/tag/v4.12.2","https://github.com/honojs/hono/security/advisories/GHSA-xh87-mx6m-69f3"],"products":["hono:hono"],"source":"nvd","synced_at":"2026-10-19T22:24:17.937441719+00:00"},"epss":{"cve":"CVE-2026-27700","score":0.00269,"percentile":0.19109,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-xh87-mx6m-69f3","url":"https://osv.dev/vulnerability/GHSA-xh87-mx6m-69f3","summary":"Hono is Vulnerable to Authentication Bypass by IP Spoofing in AWS Lambda ALB conninfo","modified":"2026-09-10T03:50:36.121374455Z","packages":[{"ecosystem":"npm","name":"hono","purl":"pkg:npm/hono","ranges":[">=4.12.0 <4.12.2"],"fixed":["4.12.2"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}