A NULL pointer dereference is present in libyang before v1.0-r3 in the function lys_extension_instances_free() due to a copy of unresolved extensions in lys_restr_dup(). Applications that use libyang to parse untrusted input yang files may crash.Referenceshttps://github.com/CESNET/libyang/compare/v1.0-r2...v1.0-r3https://github.com/CESNET/libyang/commit/7852b272ef77f8098c35deea6c6f09cb78176f08https://github.com/CESNET/libyang/issues/773https://bugzilla.redhat.com/show_bug.cgi?id=1793935https://lists.debian.org/debian-lts-announce/2023/09/msg00019.html
