A new paper names 'instruction privilege escalation': agent harnesses assemble context in ways that can promote low-privilege content into a higher instruction tier, so a model follows attacker text it would have ignored at the original level. Across 13 attack objectives on six coding-agent harnesses, unrestricted execution hit every objective on every harness, and automatic permission review did not save the three harnesses that offer it.
The authors also reproduce the issue with harness-provided persistent goals and scheduled tasks, which makes the attack surface broader than a single injected instruction.