Background. Jupyter notebooks are one of the main tools used by data scientists. Notebooks include features (configuration scripts, markdown, images, etc.) that make them challenging to analyze compared to traditional software. As a result, existing software engineering models, tools, and studies do not capture the uniqueness of Notebook's behavior. Aims. This paper aims to provide a large-scale empirical study of bugs and vulnerabilities in the Notebook ecosystem. Method. We collected and analyzed a large dataset of Notebooks from two major platforms. Our methodology involved quantitative analyses of notebook characteristics (such as complexity metrics, contributor activity, and documentation) to identify factors correlated with bugs. Additionally, we conducted a qualitative study using grounded theory to categorize notebook bugs, resulting in a comprehensive bug taxonomy. Finally, we analyzed security-related commits and vulnerability reports to assess risks associated with Notebook deployment frameworks. Results. Our findings highlight that configuration issues are among the most common bugs in notebook documents, followed by incorrect API usage. Finally, we explore common vulnerabilities associated with popular deployment frameworks to better understand risks associated with Notebook development. Conclusions. This work highlights that notebooks are less wellsupported than traditional software, resulting in more complex code, misconfiguration, and poor maintenance.

Harmful content embedded in program elements within source code may have detrimental impact on mental health of software developers, and promote harmful behavior. Our key insight is that software developers may introduce harmful content into source code via diverse semantic-preserving program transformations when using Code Large Language Models (Code LLMs). To analyze the space of program transformations that may be used to introduce harmful content into auto-generated code, we conduct a preliminary study that revealed 32 different types of transformations that can be used to introduce harmful content in source code. Based on our study, we propose CHT, a novel coverage-based harmfulness testing framework that automatically synthesizes prompts using a set of prompt templates injected with diverse harmful keywords to perform various types of transformations on a set of mined benign programs. Instead of checking if the content moderation has been bypassed as prior testing approaches, CHT performs output damage measurement to assess potential harm that can be incurred by the generated outputs (i.e., natural language explanation and modified code). By considering output damage, CHT revealed several problems in Code LLMs: (1) bugs in content moderation for code (Code LLMs produce the harmful code without providing any warning), (2) inadequacy in performing code-related task (e.g., Code LLMs may resort to explaining the given code instead of performing the instructed transformation task), and (3) lenient content moderation (gives warning but the modified code with harmful content is still produced). Our evaluations of CHT on four Code LLMs and gpt-4o-mini (general LLM) show that content moderation in Code LLMs is relatively easy to bypass where LLMs may generate harmful keywords embedded within identifier names or code comments without giving any warning (65.93% in our evaluation). To improve the robustness of content moderation in code-related tasks, we propose a two-phase approach that checks if the prompt contains any harmful content before generating any output. Our evaluation shows that our proposed approach improves the content moderation of Code LLM by 483.76%.

Abstract Most studies on recommender systems focus on collaborative algorithm approaches over content‐based recommendation due to their better accuracy results. However, the advantage of the latter is that it is more effective and more transparent with user applications. This article proposes WordRecommender, an explainable content‐based algorithm that calculates similarity by semantic proximity. Its preprocessing step involves analyses of movie reviews to obtain aspects, defined as relevant words of high sentimental value. Recommendations are generated by a neighbourhood algorithm that calculates the similarity of films based on the semantic proximity of the aspects ordered by their emotional score. It can also consider a semantic comparison of metadata using the most related aspects from the recommended movie and one enjoyed by the user for the production of textual explanations. The accuracy of the algorithm was competitive with those of other baseline neighbourhood methods, and the semantic data of items can be the source of both representative information and reasoning in recommender systems.