A vulnerability in LLM parameter-space merging algorithms enables a latent supply-chain attack where adversaries embed pre-computed malicious weight perturbations into open-source models. Using a constrained optimization framework, attackers inject latent components into the Multilayer Perceptron (MLP) up-projection matrices of source models. These perturbations are mathematically constrained to preserve the source model's individual safety alignment (via directional consistency) and benign…
Source: arXiv