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Anthropic resumes AI cyber evaluations after Claude hacking incidents

By Thomson Reuters Aug 31, 2026 | 6:13 PM

Aug 31 (Reuters) – Anthropic said on Monday it had resumed external cybersecurity testing of AI models after deploying new safeguards, following incidents ​last month in which Claude models ‌accessed the internet and other systems during security evaluations.

Anthropic disclosed three incidents on July 30, attributing them to a misconfiguration in a third-party evaluation environment.

In response, the company said ‌it ​temporarily paused external cybersecurity evaluations ⁠of pre-release models ⁠for “several weeks” and briefly halted internal evaluations while it implemented new safeguards.

Separately, Britain’s AI Security Institute reported in August that Claude Mythos 5 took ​a series of unauthorized actions on the live internet during cybersecurity testing in which the ⁠model had been deliberately given ⁠internet access.

The AI industry is facing ​scrutiny in the United States, where the Trump administration ​has finalised the details of voluntary cybersecurity ‌tests, and the European Union, where regulators are in talks with both Anthropic and OpenAI.

The company said it “built and deployed a classifier to automatically ⁠identify, in real-time mode, when a model attempts to aggressively probe or escape a testing environment, or unexpectedly obtains ⁠internet access. ‌When the classifier flags such an ⁠attempt, it blocks the action before ​the ‌tool call is run, ends the ​task, and ⁠alerts a human.”

As part of broader security efforts, Anthropic said on Monday that it redirected about 150 product engineers to work on security.

(Reporting by Mrinmay Dey in Mexico City; Editing by Joyjeet Das and ​Sherry Jacob-Phillips)