CVE-2026-79591

Name of the Vulnerable Software and Affected Versions libxls version 1.6.3

Description Insufficient validation of a file-controlled font index in the xls getCSS() function leads to a heap-buffer-overflow and use-after-free. A heap-buffer-overflow occurs when a program writes more data to a heap-allocated buffer than it can hold, while a use-after-free happens when a program continues to use a pointer after the memory it points to has been freed.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.