CVE-2026-35598 go-vikunja CVE debrief

Who should care

Defenders managing Vikunja instances, especially those with multiple projects and CalDAV users, should assess exposure and prioritize upgrading to version 2.3.0 or later to prevent unauthorized task data access. Defenders should verify CalDAV user access controls and task data exposure, and monitor for unusual task data access patterns. The vulnerability allows authenticated CalDAV users to read full task data from any project, potentially leading to data

Why it matters

CVE-2026-35598 allows authenticated CalDAV users to read full task data from any project in Vikunja prior to version 2.3.0. Defenders should verify exposure, prioritize upgrading, and monitor for unusual access patterns.

• Potential unauthorized task data access by authenticated CalDAV users
• Need to verify CalDAV user access controls and task data exposure
• Priority on upgrading to Vikunja version 2.3.0 or later
• Monitoring for unusual task data access patterns recommended

Technical summary

The CalDAV GetResource and GetResourcesByList methods in Vikunja prior to version 2.3.0 do not verify authenticated user access to tasks by UID, allowing any authenticated CalDAV user to read full task data from any project. This vulnerability can be exploited by guessing or knowing a task's UID, potentially leading to unauthorized task data access. Defenders should prioritize verifying exposure of CalDAV users and upgrading to Vikunja version 2.3.0 or later. Inventory checks and monitoring for unusual task data access patterns are recommended.

Defensive priority

Defenders should prioritize verifying exposure of CalDAV users and upgrading to Vikunja version 2.3.0 or later. Inventory checks and monitoring for unusual task data access patterns are recommended.

Recommended defensive actions

• Verify if CalDAV users have access to task data they should not have
• Upgrade to Vikunja version 2.3.0 or later
• Monitor for unusual task data access patterns
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, its impact, and the fixed version. Vendor advisory and patch information are available through GitHub. The vulnerability was reported and fixed in version 2.3.0 of Vikunja. The CVE record provides additional context on the vulnerability, including its CVSS score and severity. Defenders should verify exposure and prioritize upgrading to the fixed version. The NVD entry also provides additional information on the vulnerability and its impact.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.