CVE-2026-33635

{"id": "CVE-2026-33635", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 1.4, "exploitabilityScore": 2.8}, {"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 1.4, "exploitabilityScore": 2.8}]}, "published": "2026-03-26T21:17:07.287", "references": [{"url": "https://github.com/icalendar/icalendar/commit/b8d23b490363ee5fffaec1d269a8618a912ca265", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/icalendar/icalendar/security/advisories/GHSA-pv9c-9mfh-hvxq", "tags": ["Exploit", "Mitigation", "Vendor Advisory"], "source": "security-advisories@github.com"}, {"url": "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/icalendar/CVE-2026-33635.yml", "tags": ["Mitigation", "Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-93"}]}], "descriptions": [{"lang": "en", "value": "iCalendar is a Ruby library for dealing with iCalendar files in the iCalendar format defined by RFC-5545. Starting in version 2.0.0 and prior to version 2.12.2, .ics serialization does not properly sanitize URI property values, enabling ICS injection through attacker-controlled input, adding arbitrary calendar lines to the output. `Icalendar::Values::Uri` falls back to the raw input string when `URI.parse` fails and later serializes it with `value.to_s` without removing or escaping `\\r` or `\\n` characters. That value is embedded directly into the final ICS line by the normal serializer, so a payload containing CRLF can terminate the original property and create a new ICS property or component. (It looks like you can inject via url, source, image, organizer, attach, attendee, conference, tzurl because of this). Applications that generate `.ics` files from partially untrusted metadata are impacted. As a result, downstream calendar clients or importers may process attacker-supplied content as if it were legitimate event data, such as added attendees, modified URLs, alarms, or other calendar fields. Version 2.12.2 contains a patch for the issue."}, {"lang": "es", "value": "iCalendar es una biblioteca de Ruby dise\u00f1ada para gestionar archivos iCalendar en el formato definido por el RFC-5545. Desde la versi\u00f3n 2.0.0 hasta la versi\u00f3n 2.12.2, la serializaci\u00f3n de archivos .ics no depura correctamente los valores de las propiedades URI, lo que permite la inyecci\u00f3n ICS a trav\u00e9s de entradas controladas por un atacante, a\u00f1adiendo entradas de calendario arbitrarias a la salida. `Icalendar::Values::Uri` recurre a la cadena de entrada sin procesar cuando `URI.parse` falla y posteriormente la serializa con `value.to_s` sin eliminar ni escapar los caracteres \\r o \\n. Ese valor se incrusta directamente en la l\u00ednea ICS final mediante el serializador normal, por lo que una carga \u00fatil que contenga CRLF puede terminar la propiedad original y crear una nueva propiedad o componente ICS. (Parece que, debido a esto, se puede inyectar a trav\u00e9s de url, source, image, organizer, attach, attendee, conference y tzurl). Las aplicaciones que generan archivos `.ics` a partir de metadatos parcialmente no fiables se ven afectadas. Como resultado, los clientes de calendario o importadores posteriores pueden procesar el contenido proporcionado por el atacante como si se tratara de datos de eventos leg\u00edtimos, tales como asistentes a\u00f1adidos, URL modificadas, alarmas u otros campos del calendario. La versi\u00f3n 2.12.2 contiene un parche para este problema."}], "lastModified": "2026-04-10T15:49:23.240", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:icalendar_project:icalendar:*:*:*:*:*:ruby:*:*", "vulnerable": true, "matchCriteriaId": "3BBE7B6B-857A-41B0-A38E-7FA77FDB1497", "versionEndExcluding": "2.12.2", "versionStartIncluding": "2.0.0"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}