# CVE-2026-79591

## Summary

- **CVE ID:** CVE-2026-79591
- **Severity:** HIGH
- **CVSS Score:** 7.8 (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Sep 10, 2026
- **Last Modified:** Sep 15, 2026

## Description

A heap-buffer-overflow and use-after-free vulnerability exists in the xls_getCSS() function of libxls 1.6.3 due to insufficient validation of a file-controlled font index.

## Affected Products

- n/a — n/a (n/a)

## References

- [CNA](https://github.com/libxls/libxls/issues/161)
- [CNA](https://github.com/libxls/libxls/pull/164/changes/902c8f9b13710c3a13b6232fb86626c5c729402c)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.13%
- **EPSS Percentile:** 2.7

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._