Three Off-the-Shelf Guardrails Cut Generative-Search Poisoning by at Most 5.7%

arXiv 2609.02316·high signalXBlueskyLinkedInCopy link

Counter-GEO-Bench targets adversarial generative engine optimization, where an attacker publishes ordinary-looking GEO-optimized pages that a generative search engine retrieves and synthesizes into distorted answers. It pairs 247 human-verified quality-gated queries with matched information-preserving and information-distorting rewrites and scores defenses on attack success rate, false positives and answer quality across three victim LLMs. Granite Guardian, Llama Guard 3 and NeMo Self-Check Fact-Checking reduced ASR by at most 5.7% relative (Granite Guardian's reduction was not statistically significant) because safety-taxonomy guardrails look for policy violations while GEO misinformation passes as fluent informational content; the paper's own C-GEO Guard baseline cut ASR 47.6% relative with near-zero utility loss.