CVE-2026-42267 MEDIUM

CVE-2026-42267: Kimai: Formula Injection via tag names in XLSX export

Vendor Kimai
Product kimai
Weakness CWE-1236
Published May 8, 2026
Last update May 8, 2026
View on NVD All CVEs

CVSS base score

5.4/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction —
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

May 8, 2026 CVE published
May 8, 2026 Record updated