{"id":"CVE-2026-27700","aliases":["GHSA-xh87-mx6m-69f3"],"url":"https://o3.security/vulnerability/CVE-2026-27700","summary":"Hono is Vulnerable to Authentication Bypass by IP Spoofing in AWS Lambda ALB conninfo","details":"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.","published":"2026-02-25T15:01:44.681Z","modified":"2026-08-07T11:50:49.981265161Z","cvss":{"score":8.2,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"hono","fixedVersion":"4.12.2"}],"fix":{"url":"https://github.com/honojs/hono/commit/41adbf56e252c04611f8972364ac0887ae07a4c7","label":"honojs/hono@41adbf5"},"references":[{"type":"WEB","url":"https://github.com/honojs/hono/releases/tag/v4.12.2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27700.json"},{"type":"ADVISORY","url":"https://github.com/honojs/hono/security/advisories/GHSA-xh87-mx6m-69f3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27700"},{"type":"FIX","url":"https://github.com/honojs/hono/commit/41adbf56e252c04611f8972364ac0887ae07a4c7"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:50:49.981265161Z"}}