{"resultsPerPage":1,"startIndex":0,"totalResults":1,"format":"NVD_CVE","version":"2.0","timestamp":"2026-04-17T12:07:48.685","vulnerabilities":[{"cve":{"id":"CVE-2026-27477","sourceIdentifier":"security-advisories@github.com","published":"2026-02-24T20:27:50.173","lastModified":"2026-02-26T21:17:15.260","vulnStatus":"Analyzed","cveTags":[],"descriptions":[{"lang":"en","value":"Mastodon is a free, open-source social network server based on ActivityPub. FASP registration requires manual approval by an administrator. In versions 4.4.0 through 4.4.13 and 4.5.0 through 4.5.6, an unauthenticated attacker can register a FASP with an attacker-chosen `base_url` that includes or resolves to a local / internal address, leading to the Mastodon server making requests to that address. This only affects Mastodon servers that have opted in to testing the experimental FASP feature by setting the environment variable `EXPERIMENTAL_FEATURES` to a value including `fasp`. An attacker can force the Mastodon server to make http(s) requests to internal systems. While they cannot control the full URL that is being requested (only the prefix) and cannot see the result of those requests, vulnerabilities or other undesired behavior could be triggered in those systems. The fix is included in the 4.4.14 and 4.5.7 releases. Admins that are actively testing the experimental \"fasp\" feature should update their systems. Servers not using the experimental feature flag `fasp` are not affected."},{"lang":"es","value":"Mastodon es un servidor de red social gratuito, de código abierto, basado en ActivityPub. El registro de FASP requiere aprobación manual por parte de un administrador. En las versiones 4.4.0 a 4.4.13 y 4.5.0 a 4.5.6, un atacante no autenticado puede registrar un FASP con una 'base_url' elegida por el atacante que incluye o se resuelve en una dirección local / interna, lo que lleva al servidor de Mastodon a realizar solicitudes a esa dirección. Esto solo afecta a los servidores de Mastodon que han optado por probar la característica experimental FASP estableciendo la variable de entorno 'EXPERIMENTAL_FEATURES' a un valor que incluya 'fasp'. Un atacante puede forzar al servidor de Mastodon a realizar solicitudes http(s) a sistemas internos. Aunque no pueden controlar la URL completa que se solicita (solo el prefijo) y no pueden ver el resultado de esas solicitudes, se podrían activar vulnerabilidades u otros comportamientos no deseados en esos sistemas. La solución está incluida en las versiones 4.4.14 y 4.5.7. Los administradores que están probando activamente la característica experimental 'fasp' deberían actualizar sus sistemas. Los servidores que no utilizan la bandera de característica experimental 'fasp' no se ven afectados."}],"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:H/VA:N/SC:N/SI:N/SA:N/E:U/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":4.6,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"UNREPORTED","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:H/PR:N/UI:N/S:U/C:N/I:H/A:N","baseScore":5.9,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":2.2,"impactScore":3.6}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Primary","description":[{"lang":"en","value":"CWE-918"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4.0","versionEndExcluding":"4.4.14","matchCriteriaId":"F8A96B12-8C08-4A0C-88A8-B7B2B7AED3BF"},{"vulnerable":true,"criteria":"cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5.0","versionEndExcluding":"4.5.7","matchCriteriaId":"65E9009A-6D3F-4758-8EAA-6D832F06F3F6"}]}]}],"references":[{"url":"https://github.com/mastodon/mastodon/commit/7b85d2182361e68d51d9a02f94fb1070b5f503b1","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/mastodon/mastodon/security/advisories/GHSA-46w6-g98f-wxqm","source":"security-advisories@github.com","tags":["Vendor Advisory","Patch"]}]}}]}