The aim of this annual report is to present an updated assessment of the threat posed by non-state actors' use of chemical, biological, radiological, or nuclear (CBRN) materials to cause adverse effects on society. The content is based solely on open source information and includes a selection of incidents. The report is produced by a research group at FOI (Swedish Defence Research Agency), with grants from the Swedish Ministry of Defence. There were no confirmed attacks with CBRN agents that caused significant adverse consequences in society during 2023. After a period of relatively few reports and events of terrorists and CBRN materials, the number of reports of propaganda and suspected CBRN-plots has now increased. This applies not least in the European context where individuals have been arrested during the last two years for possible preparations for attacks with chemical substances and/or toxins. In all cases, the law enforcement intervention occurred before a capacity to conduct an attack had been reached. These cases have primarily been linked to hydrogen cyanide and ricin, thus following earlier patterns of interest in capacity building within jihadist circles for this type of attack plots. The authors note that poisonous substances continue to be used relatively often to threaten, intimidate and harm other people. In most cases that have come to our attention, the threats have been directed at individuals who are closely related to the perpetrator. Threats referring to poisonous or infectious substances are also used for financially opportunistic purposes, or to demonstrate dissatisfaction with companies, authorities, or other public functions and people.