CVE-2026-73256

{"id": "CVE-2026-73256", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-73256", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-08-21T21:10:40.015064Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.1, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.2, "exploitabilityScore": 3.9}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "cesanta", "product": "mongoose", "versions": [{"status": "affected", "version": "< 7.22"}]}]}], "published": "2026-08-20T18:16:46.523", "references": [{"url": "https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/cesanta/mongoose/pull/3611", "tags": ["Issue Tracking", "Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/cesanta/mongoose/releases/tag/7.22", "tags": ["Release Notes"], "source": "security-advisories@github.com"}, {"url": "https://github.com/cesanta/mongoose/security/advisories/GHSA-mgp5-rjrv-h5j3", "tags": ["Exploit", "Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-444"}]}], "descriptions": [{"lang": "en", "value": "Mongoose is an embedded web server and network library. Prior to 7.22, a remote unauthenticated attacker can exploit an HTTP/1.0 reverse-proxy deployment by sending a request with Transfer-Encoding: chunked and conflicting framing. The http_cb() function in src/http.c tests hm.proto.len with an impossible greater-than-eight condition even though mg_http_parse() requires an eight-byte protocol string, so is_http_1_0 is never set. Mongoose consequently processes chunked encoding that an HTTP/1.0 proxy can ignore, enabling request smuggling and unauthorized access or state changes. This issue is fixed in version 7.22."}, {"lang": "es", "value": "Mongoose es un servidor web incrustado y una biblioteca de red. Antes de la versi\u00f3n 7.22, un atacante remoto no autenticado puede explotar una implementaci\u00f3n de proxy inverso HTTP/1.0 enviando una solicitud con Transfer-Encoding: chunked y un encuadre conflictivo. La funci\u00f3n http_cb() en src/http.c prueba hm.proto.len con una condici\u00f3n imposible de mayor que ocho, a pesar de que mg_http_parse() requiere una cadena de protocolo de ocho bytes, por lo que is_http_1_0 nunca se establece. Mongoose, en consecuencia, procesa la codificaci\u00f3n chunked que un proxy HTTP/1.0 puede ignorar, lo que permite el contrabando de solicitudes y el acceso no autorizado o cambios de estado. Este problema se corrige en la versi\u00f3n 7.22."}], "lastModified": "2026-10-18T20:10:00.110", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:cesanta:mongoose:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "455C6F41-72BB-40DA-BF44-9D7C6B0C2EB5", "versionEndExcluding": "7.22"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}