What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 5.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-08 · updated 2026-06-17
• Weakness: CWE-1236

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.

Affected products

• kimai: from 2.27.0 before 2.54.0 — fixed in 2.54.0

How to fix

Upgrade to a fixed version: kimai 2.54.0. Check the vendor advisory for mitigations.

References

• https://github.com/kimai/kimai/releases/tag/2.54.0
• https://github.com/kimai/kimai/security/advisories/GHSA-3xc2-h5r3-wv3r
• https://github.com/kimai/kimai/security/advisories/GHSA-3xc2-h5r3-wv3r

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