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Vulnerability record · CVE-2026-79591 · published 10 September 2026

CVE-2026-79591: Heap-based buffer overflow vulnerability

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.

7.8 CVSS 3.1 High EPSS 0.17% · top 93.9% CWE-122 · Heap-based buffer overflow Deferred
7.8CVSS 3.1 base score
0.17%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
3References
22 Sep 2026Last modified by NVD

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.

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References

LinkTags
https://github.com/libxls/libxls/issues/161
https://github.com/libxls/libxls/pull/164/changes/902c8f9b13710c3a13b6232fb86626c5c729402c
https://github.com/libxls/libxls/issues/161

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Source: NIST National Vulnerability Database (record CVE-2026-79591), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.