CVE-2026-42267

Medium

Description

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.

SeverityMedium

CVSS5.7

Exploit probability—

ProductKimai

PublishedMay 8, 2026

First seenMay 8, 2026

Weakness typeCWE-1236CWE-1236

How to fix

Update

kimai kimai2.54.0 or later
kimai/kimai2.54.0 or later

Affected products

Product	Affected versions	Fixed in
kimai kimai	2.27.0 ≤ v < 2.54.0	2.54.0
kimai/kimaiPackagist	2.27.0 ≤ v < 2.54.0	2.54.0

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