CVE-2026-79591

Heap Buffer Overflow and Use-After-Free in libxls xls_getCSS Function

Published Sep 10, 2026 CVSS 3.1 · 7.8 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Title Heap Buffer Overflow and Use-After-Free in libxls xls_getCSS Function
Type Values Removed Values Added
Title Heap Buffer Overflow and Use‑After‑Free in libxls xls_getCSS Function
Weaknesses CWE-416
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Libxls
Libxls libxls
Vendors & Products Libxls
Libxls libxls
Type Values Removed Values Added
Title Heap Buffer Overflow and Use‑After‑Free in libxls xls_getCSS Function
Weaknesses CWE-122
CWE-416
Type Values Removed Values Added
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.
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Sep 15, 2026, 2:11 PM
Reserved
Aug 25, 2026, 12:00 AM
Status
Deferred
Published
Sep 10, 2026, 9:17 PM
Modified
Sep 22, 2026, 8:00 PM