Online memes are often carriers of unsafe content such as disinformation and propaganda.
Their rapid evolution in response to news events and strong dependence on contextual information make it difficult for platforms and moderators to detect and moderate them effectively.
Moreover, existing moderation studies typically classify memes as safe or unsafe based on individual images, lacking the ability to perform broader provenance analysis, i.e., where a meme originates, how it spreads, what cultural symbolism it represents, whether it poses potential risks to society, etc.
To bridge this gap, we introduce MemeTrace, a multimodal LLM-based agent that automatically traces the provenance and potential risks of emerging memes.
We evaluate MemeTrace on Meme100, a dataset of 100 real-world memes, using both human annotation and automatic metrics.
The results demonstrate that MemeTrace substantially outperforms the VLM baseline.
More importantly, MemeTrace achieves higher accuracy in detecting unsafe memes, especially those involving disinformation and sensitive content, and remains robust under visual perturbations.