Vulnerability · Published Apr 10, 2026 · Assigned by GitHub_M

CVE-2026-35601Vikunja has an iCalendar Property Injection via CRLF in CalDAV Task Output

Medium 4.1

In plain English

A medium-severity security flaw in vikunja from go-vikunja. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.1Medium

Exploit odds (30 days)0.2%top 90.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	code.vikunja.io/api	2.3.0	GHSA-2g7h-7rqr-9p4r
Go	code.vikunja.io/api	no fix listed	GO-2026-4951

Affected products (as reported)

Vendor	Product	Versions
go-vikunja	vikunja	< 2.3.0

Weakness: CWE-93 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N

References

https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2g7h-7rqr-9p4r x_refsource_CONFIRM
https://github.com/go-vikunja/vikunja/pull/2580 x_refsource_MISC
https://github.com/go-vikunja/vikunja/releases/tag/v2.3.0 x_refsource_MISC