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    2 vulnerabilities by icalendar_project

    CVE-2026-33635 (GCVE-0-2026-33635)

    Vulnerability from nvd – Published: 2026-03-26 20:30 – Updated: 2026-03-30 11:33
    VLAI
    Title
    iCalendar has ICS injection via unsanitized URI property values
    Summary
    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.
    Severity
    4.3 (Medium)
    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
    SSVC
    Exploitation: poc Automatable: no Technical Impact: partial
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-93 - Improper Neutralization of CRLF Sequences ('CRLF Injection')
    Assigner
    References
    Impacted products
    Vendor Product Version
    icalendar icalendar Affected: >= 2.0.0, < 2.12.2
    		Create a notification for this product.
    Show details on NVD website
    To clipboard 

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    CVE-2026-33635 (GCVE-0-2026-33635)

    Vulnerability from cvelistv5 – Published: 2026-03-26 20:30 – Updated: 2026-03-30 11:33
    VLAI
    Title
    iCalendar has ICS injection via unsanitized URI property values
    Summary
    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.
    Severity
    4.3 (Medium)
    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
    SSVC
    Exploitation: poc Automatable: no Technical Impact: partial
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-93 - Improper Neutralization of CRLF Sequences ('CRLF Injection')
    Assigner
    References
    Impacted products
    Vendor Product Version
    icalendar icalendar Affected: >= 2.0.0, < 2.12.2
    		Create a notification for this product.
    Show details on NVD website
    To clipboard 

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