CVE-2026-44433

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{"affected": [{"affectedData": [{"product": "quicly", "vendor": "h2o", "versions": [{"status": "affected", "version": "< 8b178e6"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:h2o:quicly:*:*:*:*:*:*:*:*", "matchCriteriaId": "FD025CC7-B866-4C0E-873A-86908DC9E6BD", "versionEndExcluding": "2026-05-29", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server. Prior to commit 8b178e6, an adversarial peer could send a STREAM frame carrying just one byte at the largest offset being permitted to obtain additional flow control credit, which under certain circumstances could lead to a Denial of Service. Assuming the application prepares a receive buffer for storing all data that arrive out-of-order, up to the largest offset being received, this behavior could lead to the application allocating large amount of memory with the peer sending only a handful of packets, resulting in memory exhaustion. In addition to the receive buffer allocation strategy, the severity of this vulnerability depends on how the application controls the stream concurrency. In case of the H2O HTTP server, under its default setting, this bug increases the maximum amount of memory allocated per connection by about 4 times. This issue has been fixed by commit 8b178e6."}, {"lang": "es", "value": "Quicly es una implementaci\u00f3n del protocolo IETF QUIC destinada principalmente para su uso dentro del servidor HTTP H2O. Antes del commit 8b178e6, un par adversario pod\u00eda enviar un frame STREAM que transportaba solo un byte en el mayor offset permitido para obtener cr\u00e9dito adicional de control de flujo, lo que bajo ciertas circunstancias podr\u00eda llevar a una denegaci\u00f3n de servicio. Asumiendo que la aplicaci\u00f3n prepara un b\u00fafer de recepci\u00f3n para almacenar todos los datos que llegan fuera de orden, hasta el mayor offset recibido, este comportamiento podr\u00eda llevar a que la aplicaci\u00f3n asigne una gran cantidad de memoria con el par enviando solo un pu\u00f1ado de paquetes, resultando en agotamiento de memoria. Adem\u00e1s de la estrategia de asignaci\u00f3n del b\u00fafer de recepci\u00f3n, la gravedad de esta vulnerabilidad depende de c\u00f3mo la aplicaci\u00f3n controla la concurrencia de streams. En el caso del servidor HTTP H2O, bajo su configuraci\u00f3n predeterminada, este error aumenta la cantidad m\u00e1xima de memoria asignada por conexi\u00f3n en aproximadamente 4 veces. Este problema ha sido solucionado por el commit 8b178e6."}], "id": "CVE-2026-44433", "lastModified": "2026-10-24T20:10:00.137", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 1.4, "source": "security-advisories@github.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-44433", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-07-17T15:26:30.321361Z", "version": "2.0.3"}}]}, "published": "2026-07-16T23:16:16.727", "references": [{"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/h2o/quicly/commit/8b178e692c51a3b1031612ef89f03a53aac63c15"}, {"source": "security-advisories@github.com", "tags": ["Vendor Advisory"], "url": "https://github.com/h2o/quicly/security/advisories/GHSA-f7qr-4p37-9gx9"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-400"}, {"lang": "en", "value": "CWE-770"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{}

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