In libxml2 before 2.10.4, parsing of certain invalid XSD schemas can lead to a NULL pointer dereference and subsequently a segfault. This occurs in xmlSchemaFixupComplexType in xmlschemas.c.
https://cert-portal.siemens.com/productcert/html/ssa-556635.html
https://security.netapp.com/advisory/ntap-20240201-0005/
https://security.netapp.com/advisory/ntap-20230601-0006/
https://lists.debian.org/debian-lts-announce/2023/04/msg00031.html