CVE Explorer
CVE-2026-33635
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`
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"product":"icalendar","vendor":"icalendar","versions":[{"status":"affected","version":">= 2.0.0, < 2.12.2"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:d174ce9862fd37b235a2d80f6a070a1cd7dabb26997fc40de64c91a761298a82 · sha256:1ecdfb9ef9555936… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:d174ce9862fd37b235a2d80f6a070a1cd7dabb26997fc40de64c91a761298a82 · sha256:1ecdfb9ef9555936… · /containers/cna/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-93","description":"CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:d174ce9862fd37b235a2d80f6a070a1cd7dabb26997fc40de64c91a761298a82 · sha256:1ecdfb9ef9555936… · /containers/cna/problemTypes/0/descriptions/0
Source references
3 source assertions{"name":"https://github.com/icalendar/icalendar/commit/b8d23b490363ee5fffaec1d269a8618a912ca265","tags":["x_refsource_MISC"],"url":"https://github.com/icalendar/icalendar/commit/b8d23b490363ee5fffaec1d269a8618a912ca265"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:d174ce9862fd37b235a2d80f6a070a1cd7dabb26997fc40de64c91a761298a82 · sha256:1ecdfb9ef9555936… · /containers/cna/references/1
{"name":"https://github.com/icalendar/icalendar/security/advisories/GHSA-pv9c-9mfh-hvxq","tags":["x_refsource_CONFIRM"],"url":"https://github.com/icalendar/icalendar/security/advisories/GHSA-pv9c-9mfh-hvxq"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:d174ce9862fd37b235a2d80f6a070a1cd7dabb26997fc40de64c91a761298a82 · sha256:1ecdfb9ef9555936… · /containers/cna/references/0
{"name":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/icalendar/CVE-2026-33635.yml","tags":["x_refsource_MISC"],"url":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/icalendar/CVE-2026-33635.yml"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:d174ce9862fd37b235a2d80f6a070a1cd7dabb26997fc40de64c91a761298a82 · sha256:1ecdfb9ef9555936… · /containers/cna/references/2
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.