Kimai: Formula Injection via tag names in XLSX export
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.4epss 0.2%
exploitation probability
0.2%top 87% of all CVEs
observed exploitation
nono source reports it
In short
Kimai allows users to create tags with formula names (like =SUM(54+51)). When an admin exports timesheets to Excel, these formulas are executed automatically, potentially allowing attackers to manipulate data or cause unexpected behavior.
Technical detail
Formula injection vulnerability in Kimai 2.27.0–2.53.x via tag name input in POST /api/tags endpoint. Unprivileged ROLE_USER can inject formula strings; ArrayFormatter.formatValue() fails to sanitize tag names before passing to OpenSpout, which converts =-prefixed strings to FormulaCell objects in XLSX output. Formula execution occurs client-side when file is opened in Excel, enabling code execution or data manipulation depending on formula content.
Summary generated and translated by AI from the official 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.
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