{"id":"CVE-2026-71849","sourceIdentifier":"security-advisories@github.com","published":"2026-08-07T19:18:54.100","lastModified":"2026-10-24T15:10:00.190","vulnStatus":"Deferred","cveTags":[],"descriptions":[{"lang":"en","value":"Hono is a Web application framework that provides support for any JavaScript runtime. From 4.7.0 to 4.12.33, the Proxy Helper proxy() function in hono/proxy does not remove response headers named by the origin's Connection header. Per RFC 9110 Section 7.6.1, an intermediary must remove the header fields listed in a message's Connection header field before forwarding the message, in addition to the well known hop by hop headers, but the proxy() function only removed the well known hop by hop headers, including Connection itself, from origin responses. A client may therefore receive response headers that the origin intended only for its immediate peer, disclosing connection scoped or internal metadata contained in such headers, when an application proxies responses from an origin that declares additional, non standard headers as hop by hop via the Connection response header. This issue is fixed in version 4.12.34."},{"lang":"es","value":"Hono es un framework de aplicación web que proporciona soporte para cualquier entorno de ejecución de JavaScript. Desde la versión 4.7.0 hasta la 4.12.33, la función proxy() del Proxy Helper en hono/proxy no elimina los encabezados de respuesta nombrados por el encabezado Connection del origen. Según la Sección 7.6.1 de la RFC 9110, un intermediario debe eliminar los campos de encabezado listados en el campo de encabezado Connection de un mensaje antes de reenviar el mensaje, además de los encabezados hop by hop bien conocidos, pero la función proxy() solo eliminó los encabezados hop by hop bien conocidos, incluyendo el propio Connection, de las respuestas de origen. Un cliente puede, por lo tanto, recibir encabezados de respuesta que el origen pretendía solo para su par inmediato, divulgando metadatos internos o con ámbito de conexión contenidos en dichos encabezados, cuando una aplicación proxy las respuestas de un origen que declara encabezados adicionales, no estándar, como hop by hop a través del encabezado de respuesta Connection. Este problema está solucionado en la versión 4.12.34."}],"affected":[{"source":"security-advisories@github.com","affectedData":[{"vendor":"honojs","product":"hono","versions":[{"version":">= 4.7.0, < 4.12.34","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","baseScore":3.7,"baseSeverity":"LOW","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"NONE"},"exploitabilityScore":2.2,"impactScore":1.4}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-08-10T12:02:52.553186Z","id":"CVE-2026-71849","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-200"}]}],"references":[{"url":"https://github.com/honojs/hono/commit/720b566290793d4358bf39843adcb7cf4da4548f","source":"security-advisories@github.com"},{"url":"https://github.com/honojs/hono/releases/tag/v4.12.34","source":"security-advisories@github.com"},{"url":"https://github.com/honojs/hono/security/advisories/GHSA-79qm-7rj5-m7r9","source":"security-advisories@github.com"}]}