# Researcher reports Claude Code web-summary chain leading to code execution

_Tuesday, September 1, 2026 at 12:14 PM EDT · Security · Latest · Tier 2 — Notable_

![Researcher reports Claude Code web-summary chain leading to code execution — Primary](https://media.thenextweb.com/2026/09/laptop-code-editor-test-results-desk.jpg)

A security researcher reported that Claude Code running Opus 5 in Auto Mode could be induced to execute attacker-controlled code after being asked to summarize a webpage.

The reported chain made WebFetch fail, redirected the agent to a ZIP archive, and relied on a malicious local Python module being imported when the agent wrote its own decoder. The researcher said three tested variants succeeded in 60% to 80% of five attempts each.

Anthropic reportedly described Auto Mode as a convenience feature rather than a security guarantee.

## Sources

- [The Next Web](https://thenextweb.com/news/claude-code-prompt-injection-summarise-website-auto-mode)

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Retrieved: 2026-09-01T21:59:06.397Z
Publisher: Tech & Business (techandbusiness.org)