CVE-2026-33635

Published: Mar 26, 2026 Last Modified: Mar 26, 2026
ExploitDB:
Other exploit source:
Google Dorks:
MEDIUM 4,3
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: required
Scope: unchanged
Confidentiality: none
Integrity: low
Availability: none

Description

AI Translation Available

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.

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0003
Percentile
0,1th
Updated

Single Data Point

Only one EPSS measurement is available for this CVE. Trend analysis requires multiple data points over time.

93

Improper Neutralization of CRLF Sequences ('CRLF Injection')

Draft
Common Consequences
Security Scopes Affected:
Integrity
Potential Impacts:
Modify Application Data
Applicable Platforms
All platforms may be affected
View CWE Details
https://github.com/icalendar/icalendar/commit/b8d23b490363ee5fffaec1d269a8618a9…
https://github.com/icalendar/icalendar/security/advisories/GHSA-pv9c-9mfh-hvxq
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/icalendar/CVE-2026…