CVE-2026-27205

{"id": "CVE-2026-27205", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "impactScore": 1.4, "exploitabilityScore": 2.8}], "cvssMetricV40": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 2.3, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "LOW", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "PASSIVE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "published": "2026-02-21T06:17:00.910", "references": [{"url": "https://github.com/pallets/flask/commit/089cb86dd22bff589a4eafb7ab8e42dc357623b4", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/pallets/flask/releases/tag/3.1.3", "tags": ["Product", "Release Notes"], "source": "security-advisories@github.com"}, {"url": "https://github.com/pallets/flask/security/advisories/GHSA-68rp-wp8r-4726", "tags": ["Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-524"}]}], "descriptions": [{"lang": "en", "value": "Flask is a web server gateway interface (WSGI) web application framework. In versions 3.1.2 and below, when the session object is accessed, Flask should set the Vary: Cookie header., resulting in a Use of Cache Containing Sensitive Information vulnerability. The logic instructs caches not to cache the response, as it may contain information specific to a logged in user. This is handled in most cases, but some forms of access such as the Python in operator were overlooked. The severity and risk depend on the application being hosted behind a caching proxy that doesn't ignore responses with cookies, not setting a Cache-Control header to mark pages as private or non-cacheable, and accessing the session in a way that only touches keys without reading values or mutating the session. The issue has been fixed in version 3.1.3."}, {"lang": "es", "value": "Flask es un framework de aplicaci\u00f3n web de interfaz de puerta de enlace de servidor web (WSGI). En las versiones 3.1.2 e inferiores, cuando se accede al objeto de sesi\u00f3n, Flask deber\u00eda establecer el encabezado Vary: Cookie, lo que resulta en una vulnerabilidad de Uso de Cach\u00e9 que Contiene Informaci\u00f3n Sensible. La l\u00f3gica instruye a las cach\u00e9s a no almacenar en cach\u00e9 la respuesta, ya que puede contener informaci\u00f3n espec\u00edfica de un usuario autenticado. Esto se maneja en la mayor\u00eda de los casos, pero algunas formas de acceso, como el operador in de Python, fueron pasadas por alto. La severidad y el riesgo dependen de que la aplicaci\u00f3n est\u00e9 alojada detr\u00e1s de un proxy de cach\u00e9 que no ignore las respuestas con cookies, de no establecer un encabezado Cache-Control para marcar las p\u00e1ginas como privadas o no almacenables en cach\u00e9, y de acceder a la sesi\u00f3n de una manera que solo toque las claves sin leer los valores o mutar la sesi\u00f3n. El problema ha sido solucionado en la versi\u00f3n 3.1.3."}], "lastModified": "2026-02-24T21:59:52.183", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:palletsprojects:flask:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C52F4A9B-A92B-4063-8D3B-11DA13291DCE", "versionEndExcluding": "3.1.3"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}