{"resultsPerPage":1,"startIndex":0,"totalResults":1,"format":"NVD_CVE","version":"2.0","timestamp":"2026-04-30T02:04:00.173","vulnerabilities":[{"cve":{"id":"CVE-2026-21441","sourceIdentifier":"security-advisories@github.com","published":"2026-01-07T22:15:44.040","lastModified":"2026-01-23T09:15:47.823","vulnStatus":"Modified","cveTags":[],"descriptions":[{"lang":"en","value":"urllib3 is an HTTP client library for Python. urllib3's streaming API is designed for the efficient handling of large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once. urllib3 can perform decoding or decompression based on the HTTP `Content-Encoding` header (e.g., `gzip`, `deflate`, `br`, or `zstd`). When using the streaming API, the library decompresses only the necessary bytes, enabling partial content consumption. Starting in version 1.22 and prior to version 2.6.3, for HTTP redirect responses, the library would read the entire response body to drain the connection and decompress the content unnecessarily. This decompression occurred even before any read methods were called, and configured read limits did not restrict the amount of decompressed data. As a result, there was no safeguard against decompression bombs. A malicious server could exploit this to trigger excessive resource consumption on the client. Applications and libraries are affected when they stream content from untrusted sources by setting `preload_content=False` when they do not disable redirects. Users should upgrade to at least urllib3 v2.6.3, in which the library does not decode content of redirect responses when `preload_content=False`. If upgrading is not immediately possible, disable redirects by setting `redirect=False` for requests to untrusted source."},{"lang":"es","value":"urllib3 es una biblioteca cliente HTTP para Python. La API de streaming de urllib3 está diseñada para el manejo eficiente de grandes respuestas HTTP leyendo el contenido en fragmentos, en lugar de cargar el cuerpo completo de la respuesta en la memoria de una sola vez. urllib3 puede realizar decodificación o descompresión basándose en el encabezado HTTP 'Content-Encoding' (por ejemplo, 'gzip', 'deflate', 'br' o 'zstd'). Al usar la API de streaming, la biblioteca descomprime solo los bytes necesarios, permitiendo el consumo parcial del contenido. A partir de la versión 1.22 y antes de la versión 2.6.3, para las respuestas de redirección HTTP, la biblioteca leería el cuerpo completo de la respuesta para vaciar la conexión y descomprimir el contenido innecesariamente. Esta descompresión ocurría incluso antes de que se llamara a cualquier método de lectura, y los límites de lectura configurados no restringían la cantidad de datos descomprimidos. Como resultado, no había ninguna salvaguarda contra las bombas de descompresión. Un servidor malicioso podría explotar esto para desencadenar un consumo excesivo de recursos en el cliente. Las aplicaciones y bibliotecas se ven afectadas cuando transmiten contenido de fuentes no confiables al establecer 'preload_content=False' cuando no deshabilitan las redirecciones. Los usuarios deberían actualizar al menos a urllib3 v2.6.3, en la cual la biblioteca no decodifica el contenido de las respuestas de redirección cuando 'preload_content=False'. Si la actualización no es posible de inmediato, deshabilite las redirecciones estableciendo 'redirect=False' para las solicitudes a fuentes no confiables."}],"metrics":{"cvssMetricV40":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/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","baseScore":8.9,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"HIGH","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}],"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-409"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:*","versionStartIncluding":"1.22","versionEndExcluding":"2.6.3","matchCriteriaId":"845B6572-3E64-421E-9A0C-F94E5ED7A95B"}]}]}],"references":[{"url":"https://github.com/urllib3/urllib3/commit/8864ac407bba8607950025e0979c4c69bc7abc7b","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/urllib3/urllib3/security/advisories/GHSA-38jv-5279-wg99","source":"security-advisories@github.com","tags":["Vendor Advisory"]},{"url":"https://lists.debian.org/debian-lts-announce/2026/01/msg00017.html","source":"af854a3a-2127-422b-91ae-364da2661108"}]}}]}