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.
https://github.com/kimai/kimai/security/advisories/GHSA-3xc2-h5r3-wv3r
Published: 2026-05-08
Updated: 2026-05-13
Base Score: 6.8
Vector: CVSS2#AV:N/AC:L/Au:S/C:N/I:C/A:N
Severity: Medium
Base Score: 5.7
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N
Severity: Medium
Base Score: 6.8
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
Severity: Medium
EPSS: 0.00047