Kimai before 2.63.0 contains a business logic / improper authorization vulnerability in the team update API endpoint (PATCH /api/teams/{id}), which removes all existing team members before validating the submitted replacement member list. An authenticated teamlead (or other user) with permission to edit a team can submit a malformed members payload; although Kimai returns a validation error, the existing membership rows have already been deleted. This bypasses the dedicated member-removal endpoint's protection against removing teamleaders and can leave a team with no members or teamleaders, disrupting team-based access control.

Kimai before 2.53.0 contains an open redirect vulnerability in the SAML authentication success handler that accepts unvalidated RelayState POST parameters as redirect destinations. Attackers with IdP access can supply malicious RelayState values to redirect authenticated users to attacker-controlled URLs for credential theft or phishing attacks.

Kimai before 2.54.0 contains a timing oracle vulnerability in TokenAuthenticator that allows unauthenticated attackers to enumerate valid usernames via X-AUTH-USER header. Attackers can measure response time differences when the password hasher runs only for existing users, enabling username enumeration with no login throttling protection.

Kimai before 2.56.0 does not enforce team-membership checks in TimesheetVoter::voteOnAttribute(), which maps permissions only to own_timesheet or other_timesheet. As a result, any authenticated user with ROLE_TEAMLEAD (or a role holding edit_other_timesheet/delete_other_timesheet) can read, modify, and permanently delete timesheets belonging to any user system-wide via the API, regardless of team membership. Timesheet IDs are sequential integers and trivially enumerable. ROLE_USER accounts are correctly restricted. (Note: the maintainers characterize this behavior as matching the documented permission model.)

Kimai before 2.62.0 fails to validate create_other_timesheet permission in the QuickEntry controller when creating new timesheets. Authenticated users with view_other_timesheet and edit_other_timesheet permissions can create timesheet records for team members by submitting the QuickEntry form, bypassing authorization checks enforced elsewhere.

Kimai versions before 2.56.0 fail to restrict the config() Twig function in sandboxed invoice and export templates, allowing administrators to access arbitrary configuration keys. Attackers with admin privileges can upload malicious templates to exfiltrate server-wide secrets including LDAP bind passwords and SAML private keys into invoice or export documents accessible to lower-privileged users.

Kimai before 2.53.0 fails to block sensitive User methods in the Twig invoice template sandbox, allowing admins to call getApiToken() and getPlainApiToken() methods. Attackers with template creation permissions can embed these method calls in invoice templates to leak hashed API tokens in rendered invoice output.

Kimai is an open-source time tracking application. Prior to version 2.54.0, the Team API endpoints use #[IsGranted('edit_team')] instead of #[IsGranted('edit', 'team')], causing Symfony TeamVoter to abstain from voting. This removes entity-level ownership checks on team operations, allowing any user with the edit_team permission to modify any team, not just teams they are authorized to manage. This issue has been patched in version 2.54.0.

Kimai is an open-source time tracking application. From version 2.27.0 to before version 2.54.0, any ROLE_USER can create a tag with a formula string as its name (e.g. =SUM(54+51)) via POST /api/tags and assign it to a timesheet. When an admin exports timesheets to XLSX, ArrayFormatter.formatValue() joins tag names with implode() and returns the result unchanged. OpenSpout promotes any =-prefixed string to a FormulaCell, writing <f>SUM(54+51)</f> into the XLSX archive. Excel evaluates the formula when the file is opened. This issue has been patched in version 2.54.0.

Kimai is an open-source time tracking application. From version 2.32.0 to before version 2.56.0, users with the role System-Admin (ROLE_SYSTE_ADMIN) and the permission upload_invoice_template can upload PDF invoice templates, which can call pdfContext.setOption('associated_files', ...) inside the sandboxed Twig render. This is forwarded to mPDF's SetAssociatedFiles(), whose writer calls file_get_contents($entry['path']) during PDF output and embeds the bytes as a FlateDecode stream in the PDF. Any file readable by the PHP worker is returned to the attacker inside the rendered invoice. This issue has been patched in version 2.56.0.