xlnt-Community xlnt Null Pointer Dereference Vulnerability in XLSX File Parser

A null pointer dereference vulnerability has been identified in xlnt-Community xlnt versions through 1.6.1. The issue arises in the XLSX file parser component, specifically within the 'xlnt::detail::xlsx_consumer::read_office_document' function of 'source/detail/serialization/xlsx_consumer.cpp'. This vulnerability leads to a segmentation fault when the application attempts to process document relationships in a malformed XLSX file, causing a crash. The vulnerability must be exploited locally, and a public exploit is available.

Impact

Exploitation of this vulnerability causes a segmentation fault due to a null pointer dereference, leading to a crash of the application.

Reproduction

The vulnerability can be reproduced by building xlnt with release optimization and AddressSanitizer (ASan) enabled. After compiling the application, it can be run with a malformed XLSX file that triggers the null pointer dereference. The AddressSanitizer will report the segmentation fault, indicating that the vulnerability has been successfully exploited.