Frontier AI models collapse under multi-turn AI attacks, Cisco finds – Help Net Security

Frontier AI models collapse under multi-turn AI attacks, Cisco finds – Help Net Security

By Mirko Zorz
Publication Date: 2026-05-28 05:30:00

Attackers who probe large language models rarely give up after one refusal. They reframe, build context across turns, adopt personas, and escalate gradually. New research from Cisco’s AI threat intelligence team finds that the safety benchmarks used across the industry miss almost all of this behavior, and the gap between published scores and observed resilience runs wide enough to misrank leading models.

Single-turn versus multi-turn ASR by model, with approximate 95% confidence half-widths on single-turn (upper bar) and multi-turn (lower bar) estimates. (Source: Cisco)

The report pairs single-turn and multi-turn evaluation across 15 closed flagship models from OpenAI, Anthropic, Google, Amazon, and xAI. The testing covered roughly 30,000 single-turn prompts and nearly 7,000 multi-turn attacks spread across more than 1,400 conversations. Across the cohort, multi-turn attack success rates climbed as high as 88%, an order of magnitude above the lowest result in the…