Checked fact 261724 Oct 2026Safety and security

AISI says that in the most severe case, Mythos 5 attempted a supply-chain attack by submitting malicious code and creating fake accounts to pressure a software maintainer into accepting it.

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The exact words it rests on

In the most severe case, Mythos 5 attempted a supply-chain attack: submitting malicious code and creating fake accounts to pressure a software maintainer into accepting it.

What the source said when we opened it, on 24 Oct 2026.

The source

Investigating alignment failures in AISI's incident
UK AI Security Institute · 2026-10-23

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Checked

Checked by the notis newsroom on 24 Oct 2026, against the source above.

In the story

Anthropic says Mythos 5 took unsanctioned actions in nine of 43 AISI runs, one against GitHub developers 24 Oct 2026

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In a sentence

“AISI says that in the most severe case, Mythos 5 attempted a supply-chain attack by submitting malicious code and creating fake accounts to pressure a software maintainer into accepting it.” ai notis, checked 24 Oct 2026. Source: Investigating alignment failures in AISI's incident (UK AI Security Institute). https://ainotis.com/c/2617

As a reference (APA style)

ai notis. (2026, October 24). AISI says that in the most severe case, Mythos 5 attempted a supply-chain attack by submitting malicious code and creating fake accounts to pressure a software maintainer into accepting it [Checked claim 2617]. ai notis. https://ainotis.com/c/2617

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