CVE-2026-27633

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{"affected": [{"affectedData": [{"product": "TinyWeb", "vendor": "maximmasiutin", "versions": [{"status": "affected", "version": "< 2.02"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:ritlabs:tinyweb:*:*:*:*:*:*:*:*", "matchCriteriaId": "8AAA8D54-16C4-42CC-A7B8-6CDCFAA96A00", "versionEndExcluding": "2.02", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "TinyWeb is a web server (HTTP, HTTPS) written in Delphi for Win32. Versions prior to version 2.02 have a Denial of Service (DoS) vulnerability via memory exhaustion. Unauthenticated remote attackers can send an HTTP POST request to the server with an exceptionally large `Content-Length` header (e.g., `2147483647`). The server continuously allocates memory for the request body (`EntityBody`) while streaming the payload without enforcing any maximum limit, leading to all available memory being consumed and causing the server to crash. Anyone hosting services using TinyWeb is impacted. Version 2.02 fixes the issue. The patch introduces a `CMaxEntityBodySize` limit (set to 10MB) for the maximum size of accepted payloads. As a temporary workaround if upgrading is not immediately possible, consider placing the server behind a Web Application Firewall (WAF) or reverse proxy (like nginx or Cloudflare) configured to explicitly limit the maximum allowed HTTP request body size (e.g., `client_max_body_size` in nginx)."}, {"lang": "es", "value": "TinyWeb es un servidor web (HTTP, HTTPS) escrito en Delphi para Win32. Las versiones anteriores a la versi\u00f3n 2.02 tienen una vulnerabilidad de denegaci\u00f3n de servicio (DoS) a trav\u00e9s del agotamiento de la memoria. Atacantes remotos no autenticados pueden enviar una solicitud POST HTTP al servidor con una cabecera 'Content-Length' excepcionalmente grande (p. ej., '2147483647'). El servidor asigna continuamente memoria para el cuerpo de la solicitud ('EntityBody') mientras transmite la carga \u00fatil sin imponer ning\u00fan l\u00edmite m\u00e1ximo, lo que lleva a que toda la memoria disponible sea consumida y provoca la ca\u00edda del servidor. Cualquiera que aloje servicios usando TinyWeb se ve afectado. La versi\u00f3n 2.02 corrige el problema. El parche introduce un l\u00edmite 'CMaxEntityBodySize' (establecido en 10MB) para el tama\u00f1o m\u00e1ximo de las cargas \u00fatiles aceptadas. Como soluci\u00f3n alternativa temporal si la actualizaci\u00f3n no es posible de inmediato, considere colocar el servidor detr\u00e1s de un Cortafuegos de Aplicaciones Web (WAF) o un proxy inverso (como nginx o Cloudflare) configurado para limitar expl\u00edcitamente el tama\u00f1o m\u00e1ximo permitido del cuerpo de la solicitud HTTP (p. ej., 'client_max_body_size' en nginx)."}], "id": "CVE-2026-27633", "lastModified": "2026-06-17T10:27:25.627", "metrics": {"cvssMetricV31": [{"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"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.7, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-27633", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-02-26T16:51:28.103829Z", "version": "2.0.3"}}]}, "published": "2026-02-26T00:16:24.130", "references": [{"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/maximmasiutin/TinyWeb/commit/1cb5a1d"}, {"source": "security-advisories@github.com", "tags": ["Vendor Advisory"], "url": "https://github.com/maximmasiutin/TinyWeb/security/advisories/GHSA-992w-gmcm-fmgr"}, {"source": "security-advisories@github.com", "tags": ["Third Party Advisory"], "url": "https://www.masiutin.net/tinyweb-cve-2026-27633.html"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-400"}], "source": "security-advisories@github.com", "type": "Secondary"}, {"description": [{"lang": "en", "value": "CWE-770"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,2.02)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "TinyWeb", "source": "cna", "vendor": "maximmasiutin"}, "product": "tinyweb", "vendor": "maximmasiutin"}], "analysis": {"en": {"generated_at": "2026-04-17T14:44:17.019783+00:00", "value": {"mitigation_remediation": ["Upgrade TinyWeb to version 2.02 or later, which implements a 10\u202fMB maximum entity body size.", "If an immediate upgrade is not possible, apply the patch from the referenced commit that introduces the CMaxEntityBodySize limit.", "Configure a front\u2011end WAF or reverse proxy such as nginx or Cloudflare to enforce a lower maximum request body size (e.g., client_max_body_size) to block oversized POST requests before they reach TinyWeb."], "summary": {"action": "Immediate Patch", "impact": "Denial of Service via memory exhaustion, caused by unbounded Content-Length handling."}, "threat_synthesis": {"affected_systems": "All hosts running TinyWeb versions earlier than 2.02 are vulnerable. The affected vendor is maximmasiutin (TinyWeb). The security advisory specifies that any deployment of TinyWeb before the 2.02 release is impacted.", "description_and_impact": "TinyWeb, a Delphi\u2011based HTTP/HTTPS server, allows an unauthenticated attacker to trigger a denial of service by sending a POST request whose Content\u2011Length header is exceptionally large. The server streams the incoming payload into memory without enforcing a maximum limit, allocating memory continuously for the body until system memory is exhausted and the process terminates. The weakness aligns with CWE\u2011400 (Uncontrolled Resource Consumption) and CWE\u2011770 (Allocation of Unbounded Resources).", "risk_and_exploitability": "The flaw achieves remote denial of service; no authentication is required. The CVSS base score is 8.7, indicating high severity. EPSS indicates a very low exploitation probability (<1\u202f%), and the vulnerability is not listed in CISA\u2019s KEV catalog, suggesting no known large\u2011scale attacks yet. Nevertheless, the remote attacker can easily send the crafted POST request to cause the server to crash, disrupting services until a reboot or reimplementation occurs."}}}}, "created": "2026-02-26T13:10:40.446027+00:00", "updated": "2026-04-17T14:45:21.043313+00:00", "vendors": ["maximmasiutin", "maximmasiutin$PRODUCT$tinyweb"]}