CVE-2026-3663 xlnt-community xlnt XLSX File compound_document.cpp xsgetn out-of-bounds

A vulnerability was found in xlnt-community xlnt up to 1.6.1. This issue affects the function xlnt::detail::compounddocumentistreambuf::xsgetn of the file source/detail/cryptography/compounddocument.cpp of the component XLSX File Parser. Performing a manipulation results in out-of-bounds read. Th...