CVE-2026-27824

{"id": "CVE-2026-27824", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-27824", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-03-02T12:54:19.314863Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "impactScore": 1.4, "exploitabilityScore": 3.9}, {"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "impactScore": 1.4, "exploitabilityScore": 3.9}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "kovidgoyal", "product": "calibre", "versions": [{"status": "affected", "version": "< 9.4.0"}]}]}], "published": "2026-02-27T20:21:39.973", "references": [{"url": "https://github.com/kovidgoyal/calibre/security/advisories/GHSA-vhxc-r7v8-2xrw", "tags": ["Exploit", "Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-307"}, {"lang": "en", "value": "CWE-346"}]}], "descriptions": [{"lang": "en", "value": "calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Prior to version 9.4.0, the calibre Content Server's brute-force protection mechanism uses a ban key derived from both `remote_addr` and the `X-Forwarded-For` header. Since the `X-Forwarded-For` header is read directly from the HTTP request without any validation or trusted-proxy configuration, an attacker can bypass IP-based bans by simply changing or adding this header, rendering the brute-force protection completely ineffective. This is particularly dangerous for calibre servers exposed to the internet, where brute-force protection is the primary defense against credential stuffing and password guessing attacks. Version 9.4.0 contains a fix for the issue."}, {"lang": "es", "value": "calibre es un gestor de libros electr\u00f3nicos multiplataforma para ver, convertir, editar y catalogar libros electr\u00f3nicos. Antes de la versi\u00f3n 9.4.0, el mecanismo de protecci\u00f3n contra fuerza bruta del servidor de contenido de calibre utiliza una clave de prohibici\u00f3n derivada tanto de 'remote_addr' como del encabezado 'X-Forwarded-For'. Dado que el encabezado 'X-Forwarded-For' se lee directamente de la solicitud HTTP sin ninguna validaci\u00f3n o configuraci\u00f3n de proxy de confianza, un atacante puede eludir las prohibiciones basadas en IP simplemente cambiando o a\u00f1adiendo este encabezado, lo que hace que la protecci\u00f3n contra fuerza bruta sea completamente ineficaz. Esto es particularmente peligroso para los servidores de calibre expuestos a internet, donde la protecci\u00f3n contra fuerza bruta es la defensa principal contra ataques de relleno de credenciales y adivinaci\u00f3n de contrase\u00f1as. La versi\u00f3n 9.4.0 contiene una soluci\u00f3n para el problema."}], "lastModified": "2026-06-17T10:27:44.763", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:calibre-ebook:calibre:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "3665E54E-5F8D-405A-BA97-8DD783962094", "versionEndExcluding": "9.4.0"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}