CVE-2026-52820 kimai CVE debrief

Who should care

Defenders responsible for Kimai deployments should assess exposure and apply the fix to prevent unauthorized project attribution and metadata retrieval. This includes verifying the current version of Kimai, applying the fix, and monitoring for unauthorized activities. Security teams and vulnerability management teams should prioritize this fix based on the potential impact on project and customer metadata security.

Why it matters

CVE-2026-52820 allows unauthorized project attribution and metadata retrieval in Kimai. Defenders should verify exposure and apply the fix.

• Verify exposure by checking if the current version of Kimai is prior to 2.57.0.
• Apply the fix by upgrading to version 2.57.0 or later.
• Monitor for unauthorized project attribution and metadata retrieval attempts.

Technical summary

The vulnerability is caused by the lack of proper validation of user-controlled project identifiers in the PATCH /api/timesheets/{id} and POST /api/timesheets endpoints. This allows an authenticated user with edit_own_timesheet privileges to assign a timesheet to a project outside their teams, persist unauthorized project attribution, and retrieve project and customer metadata. The issue is fixed in version 2.57.0 of Kimai, which implements TimesheetTeamAccessValidator to check changed project and activity associations against current team access.

Defensive priority

Defenders should prioritize verifying exposure and applying the fix, as the vulnerability allows unauthorized project attribution and metadata retrieval.

Recommended defensive actions

• Verify exposure by checking if the current version of Kimai is prior to 2.57.0.
• Apply the fix by upgrading to version 2.57.0 or later.
• Monitor for unauthorized project attribution and metadata retrieval attempts.
• 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 vulnerability is described in the CVE record and NVD entry. The fix is available in version 2.57.0 of Kimai. Evidence is limited to public CVE details and NVD assessments. Defenders should verify exposure by checking the current Kimai version and apply the fix. Additional verification may be necessary based on specific deployment configurations.

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.