{"id":"CVE-2026-27700","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-27700","generatedAt":"2026-10-28T05:59:21.829Z","title":"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.","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.","published":"2026-02-25T16:23:26.000Z","lastModified":"2026-06-17T10:27:32.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"},"cwe":["CWE-290","CWE-345"],"affected":["hono/hono"],"epss":{"score":0.00269,"percentile":0.18953,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.27%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/honojs/hono/commit/41adbf56e252c04611f8972364ac0887ae07a4c7","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/honojs/hono/releases/tag/v4.12.2","tags":["Product","Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/honojs/hono/security/advisories/GHSA-xh87-mx6m-69f3","tags":["Vendor Advisory"],"source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-27700","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}