CVE-2026-29772

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{"affected": [{"affectedData": [{"product": "astro", "vendor": "withastro", "versions": [{"status": "affected", "version": "< 10.0.0"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:astro:\\@astrojs\\/node:*:*:*:*:*:node.js:*:*", "matchCriteriaId": "315766F8-1240-4160-98C4-652A21AF6CED", "versionEndExcluding": "10.0.0", "versionStartIncluding": "9.0.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Astro is a web framework. Prior to version 10.0.0, Astro's Server Islands POST handler buffers and parses the full request body as JSON without enforcing a size limit. Because JSON.parse() allocates a V8 heap object for every element in the input, a crafted payload of many small JSON objects achieves ~15x memory amplification (wire bytes to heap bytes), allowing a single unauthenticated request to exhaust the process heap and crash the server. The /_server-islands/[name] route is registered on all Astro SSR apps regardless of whether any component uses server:defer, and the body is parsed before the island name is validated, so any Astro SSR app with the Node standalone adapter is affected. This issue has been patched in version 10.0.0."}, {"lang": "es", "value": "Astro es un framework web. Antes de la versi\u00f3n 10.0.0, el gestor POST de Server Islands de Astro almacena en b\u00fafer y analiza el cuerpo completo de la solicitud como JSON sin aplicar un l\u00edmite de tama\u00f1o. Debido a que JSON.parse() asigna un objeto de pila V8 para cada elemento en la entrada, una carga \u00fatil manipulada de muchos objetos JSON peque\u00f1os logra una amplificaci\u00f3n de memoria de ~15x (bytes en tr\u00e1nsito a bytes en pila), permitiendo que una \u00fanica solicitud no autenticada agote la pila del proceso y bloquee el servidor. La ruta /_server-islands/[name] est\u00e1 registrada en todas las aplicaciones Astro SSR independientemente de si alg\u00fan componente utiliza server:defer, y el cuerpo se analiza antes de que se valide el nombre de la isla, por lo que cualquier aplicaci\u00f3n Astro SSR con el adaptador aut\u00f3nomo de Node se ve afectada. Este problema ha sido parcheado en la versi\u00f3n 10.0.0."}], "id": "CVE-2026-29772", "lastModified": "2026-06-17T10:29:51.450", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 5.9, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}, {"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"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-29772", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-03-24T20:16:28.699372Z", "version": "2.0.3"}}]}, "published": "2026-03-24T19:16:51.153", "references": [{"source": "security-advisories@github.com", "tags": ["Exploit", "Vendor Advisory"], "url": "https://github.com/withastro/astro/security/advisories/GHSA-3rmj-9m5h-8fpv"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-770"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,10.0.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "astro", "source": "cna", "vendor": "withastro"}, "product": "astro", "vendor": "withastro"}], "analysis": {"en": {"generated_at": "2026-03-26T02:56:28.213053+00:00", "value": {"mitigation_remediation": ["Upgrade Astro to version 10.0.0 or later.", "If an upgrade is not feasible, enforce request size limits at the application or reverse proxy level.", "After applying the patch or implementing limits, restart the Astro server to clear allocated memory."], "summary": {"action": "Patch Immediately", "impact": "Denial of Service via memory exhaustion"}, "threat_synthesis": {"affected_systems": "Astro implementations using the Node standalone adapter are affected. The /_server\u2011islands/[name] route is present on all Astro SSR applications, regardless of whether any component uses server:defer, meaning that any Astro SSR app built with Node adapter and running a version earlier than 10.0.0 falls within the scope. Vendors: withastro:astro. Products: Astro web framework, versions up to 9.x, any SaaS sites or self\u2011hosted deployments using Node.", "description_and_impact": "The vulnerability arises from Astro's Server Islands POST handler, which buffers and parses the entire request body as JSON without a size restriction. Because JSON.parse allocates a V8 heap object for every element in the input, an attacker can send a crafted payload containing many small JSON objects that amplifies memory consumption roughly fifteen times the amount of raw data. When the payload triggers a heap exhaustion, the Node.js process crashes, denying service. This flaw is represented by CWE\u2011770 and allows unauthenticated attackers to cause a denial of service by exhausting server memory.", "risk_and_exploitability": "The CVSS score is 5.9, indicating a medium severity. EPSS is below 1%, suggesting that known exploitation probability is low, and the vulnerability is not listed in the CISA KEV catalog. Attackers can trigger the flaw by sending an unauthenticated HTTP POST request to the /_server\u2011islands endpoint with a large JSON payload. The attack requires no special credentials and bypasses validation checks because the body is parsed before the island name is validated. Therefore, protecting the service by patching or limiting request size is essential to mitigate the risk."}}}}, "created": "2026-03-25T11:46:32.535076+00:00", "updated": "2026-03-26T12:18:53.081858+00:00", "vendors": ["withastro", "withastro$PRODUCT$astro"]}