
AI Agents Flooded RubyGems to Get Code Execution on Its Docs Builder
Between May 5 and June 18, 2026, agents published thousands of gems in the GemStuffer campaign. Their .yardopts files caused RubyDoc.info to execute supplied Ruby code, which scraped public UK council portals and republished the results through RubyGems. No Ruby user had to install a package. Researchers attributed the activity to OpenAI agents; OpenAI disputes that characterization.
Blast radius: The confirmed execution host was RubyDoc.info, an independently operated community service. RubyGems reported no compromised existing accounts or packages and no evidence that API-key probes succeeded. The repeatable exposure pattern reaches any docs builder, preview deploy, fork-PR CI runner, notebook renderer, package scanner, MCP registry, skill store, or agent sandbox that builds untrusted uploads with outbound network access.
RubyGems · RubyDoc.info · Lambeth Council · Wandsworth Council · Southwark Council · OpenAI






