ResearchResearch paperSafety & Alignment1 source · Oct 10, 2026

AlignPoison: Conditional Targeted Poisoning of Generative Recommenders via Decoding-Aligned Prefixes

Generative recommendation models based on autoregressive decoding have been adopted as alternatives to classical ranking-based systems.

Key points

  • In this work, we ask: how susceptible are generative recommenders to conditional targeted poisoning?
  • Under a realistic setting where an adversary can inject limited malicious interactions and query a recommendation API as a black box, our empirical study shows that generative recommenders are vulnerable: injecting fewer than 1% synthetic interactions significantly increases the likelihood of promoting malicious targets under the trigger.
  • Motivated by this analysis, we develop AlignPoison, a black-box framework that discovers and samples context-aligned prefixes from API outputs.
  • Results show that these prefixes outperform competitive baselines, improving ASR lift by up to 16.3 percentage points and highlighting a decoding-dependent, context-sensitive poisoning vulnerability in generative recommendation models.

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