The vulnerability resides in the xlsx_consumer.cpp module of the xlnt C++ library, specifically in the read_office_document function. Improper handling of certain XLSX inputs can trigger a null pointer dereference, causing the application to crash or terminate abnormally. This flaw is catalogued under CWE‑476 (Uninitialized Pointer Dereference) and CWE‑404 (Improper Resource Shutdown or Release).

xlnt-community’s xlnt library, versions up to and including 1.6.1, is affected. Any application that incorporates this library and processes external XLSX files without additional validation may experience a crash.

The CVSS score of 4.8 indicates moderate severity, and the EPSS score is below 1 %, meaning a low but non‑zero likelihood of exploitation. The vulnerability is not listed in the CISA KEV catalog. Attack must be carried out locally: a user with local or privileged access can supply a crafted XLSX file that triggers the null pointer dereference. Publicly available exploit code exists, enabling a local adversary to cause a denial of service if the library operates in an untrusted context.