CVE-2025-12999

{"id": "CVE-2025-12999", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-12999", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-09-21T13:52:33.084906Z"}}], "cvssMetricV40": [{"type": "Secondary", "source": "emo@eclipse.org", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 9.1, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:H/SI:H/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "HIGH", "vulnAvailabilityImpact": "LOW", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "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"}}]}, "affected": [{"source": "emo@eclipse.org", "affectedData": [{"vendor": "Eclipse Foundation", "product": "Eclipse Open VSX", "versions": [{"status": "affected", "version": "0.6.0", "versionType": "semver", "lessThanOrEqual": "1.1.2"}], "defaultStatus": "unaffected"}]}], "published": "2026-09-21T09:17:04.533", "references": [{"url": "https://github.com/eclipse-openvsx/openvsx/pull/2196", "source": "emo@eclipse.org"}, {"url": "https://github.com/eclipse-openvsx/openvsx/security/advisories/GHSA-f55q-5m46-rmxc", "source": "emo@eclipse.org"}, {"url": "https://gitlab.eclipse.org/security/cve-assignment/-/work_items/75", "source": "emo@eclipse.org"}, {"url": "https://github.com/eclipse-openvsx/openvsx/security/advisories/GHSA-f55q-5m46-rmxc", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "description": [{"lang": "en", "value": "CWE-345"}]}], "descriptions": [{"lang": "en", "value": "UrlUtil.getBaseUrl builds the absolute URLs in a response \u2014 download links, icons, asset and API URLs \u2014 from the X-Forwarded-Host, X-Forwarded-Proto and X-Forwarded-Prefix request headers, with no check on whether the sender was a trusted proxy, falling back to the client-supplied Host header. \n\n \n\n\nThose responses are cached under keys that do not include the host (extension.json since 0.6.0, namespace.details.json since 0.9.0, sitemap since 0.14.5, latest.extension.version.vscode since 0.34.2). A single request carrying a forged header therefore places attacker-chosen URLs into an entry served to every other client for the lifetime of that entry \u2014 one hour by default, and cluster-wide where ovsx.redis.enabled is set.\n\n\n\nThe VSIX download URL, its signature URL and the public key URL are all derived from the same base URL, so extension signing does not limit the impact: an attacker who poisons an entry supplies the package, the signature over it, and the key used to verify it. \n\n\n\nExploitability depends on deployment topology. A server reachable directly by clients, or fronted by a proxy that relays the client's X-Forwarded-Host rather than overwriting it, is exploitable by an unauthenticated remote attacker. A proxy that overwrites the header is not.\n\n\n\nAn unauthenticated attacker can poison Open VSX's per-extension metadata cache with attacker-controlled download, signature, and public-key URLs by supplying a crafted X-Forwarded-Host header, causing downstream VS Code-compatible editors to fetch and install a malicious VSIX.\n\n\n\nWorkarounds (unpatched versions)\n\n \n\n\n1. Configure the reverse proxy to set rather than relay X-Forwarded-Host, X-Forwarded-Proto and X-Forwarded-Prefix \u2014 note that nginx's $host is the client's Host header and is not a safe value.\n\n\n\n2. Ensure the server is not reachable except through that proxy.\n\n\n\n3. Flush the caches afterwards; poisoned entries survive the configuration change."}, {"lang": "es", "value": "UrlUtil.getBaseUrl construye las URL absolutas en una respuesta - enlaces de descarga, iconos, activos y URL de la API - a partir de los encabezados de solicitud X-Forwarded-Host, X-Forwarded-Proto y X-Forwarded-Prefix, sin verificar si el remitente era un proxy de confianza, recurriendo al encabezado Host proporcionado por el cliente.\n\nEsas respuestas se almacenan en cach\u00e9 bajo claves que no incluyen el host (extension.json desde 0.6.0, namespace.details.json desde 0.9.0, sitemap desde 0.14.5, latest.extension.version.vscode desde 0.34.2). Por lo tanto, una \u00fanica solicitud que contenga un encabezado falsificado coloca URL elegidas por el atacante en una entrada servida a cada otro cliente durante la vida \u00fatil de esa entrada - una hora por defecto, y a nivel de cl\u00faster donde ovsx.redis.enabled est\u00e1 configurado.\n\nLa URL de descarga de VSIX, su URL de firma y la URL de clave p\u00fablica se derivan de la misma URL base, por lo que la firma de la extensi\u00f3n no limita el impacto: un atacante que envenena una entrada proporciona el paquete, la firma del mismo y la clave utilizada para verificarlo.\n\nLa explotabilidad depende de la topolog\u00eda de despliegue. Un servidor accesible directamente por los clientes, o que est\u00e1 detr\u00e1s de un proxy que retransmite el X-Forwarded-Host del cliente en lugar de sobrescribirlo, es explotable por un atacante remoto no autenticado. Un proxy que sobrescribe el encabezado no lo es.\n\nUn atacante no autenticado puede envenenar la cach\u00e9 de metadatos por extensi\u00f3n de Open VSX con URL de descarga, firma y clave p\u00fablica controladas por el atacante al proporcionar un encabezado X-Forwarded-Host manipulado, lo que provoca que los editores compatibles con VS Code posteriores obtengan e instalen un VSIX malicioso.\n\nSoluciones alternativas (versiones sin parchear)\n\n1. Configure el proxy inverso para que establezca en lugar de retransmitir X-Forwarded-Host, X-Forwarded-Proto y X-Forwarded-Prefix - tenga en cuenta que $host de nginx es el encabezado Host del cliente y no es un valor seguro.\n\n2. Aseg\u00farese de que el servidor no sea accesible excepto a trav\u00e9s de ese proxy.\n\n3. Vac\u00ede las cach\u00e9s despu\u00e9s; las entradas envenenadas sobreviven al cambio de configuraci\u00f3n."}], "lastModified": "2026-10-14T13:10:00.187", "sourceIdentifier": "emo@eclipse.org"}