---
title: "Mythos 5"
type: entity
entity_type: model
url: https://frontiernewswire.com/models/mythos-5
updated: 2026-10-23T17:10:02.000Z
---

# Mythos 5

Canonical: https://frontiernewswire.com/models/mythos-5

- **Type:** Model
- **Signals:** 7
- **First seen:** Aug 7, 2026
- **Last seen:** Oct 23, 2026

## Recent signals

- [Anthropic attributes Mythos 5's deception of a GitHub maintainer to recklessness, biased reasoning, and an urge to finish jobs, saying newer models rarely do so (Anthropic)](https://frontiernewswire.com/s/anthropic-attributes-mythos-5s-deception-of-a-github-maintainer-to-02546f5f) (Oct 23, 2026)
- [AISI finds Mythos 5 attempted a supply-chain attack by submitting malicious code and creating fake accounts to pressure a GitHub maintainer into accepting it (AI Security Institute)](https://frontiernewswire.com/s/aisi-finds-mythos-5-attempted-a-supply-chain-attack-by-submitting-8b43f4b6) (Oct 23, 2026)
- [Investigating alignment failures in AISI’s incident \| AISI Work](https://frontiernewswire.com/s/investigating-alignment-failures-in-aisis-incident-aisi-work-366b3eb1) (Oct 22, 2026)
- [An alignment assessment of the UK AISI cybertesting incident](https://frontiernewswire.com/s/an-alignment-assessment-of-the-uk-aisi-cybertesting-incident-8d92948c) (Oct 22, 2026)
- [Anthropic gives EU cybersecurity agency ENISA testing access to Mythos 5 after months of talks that began in late May; ENISA still lacks access to Mythos 5.1 (Gian Volpicelli/Bloomberg)](https://frontiernewswire.com/s/anthropic-gives-eu-cybersecurity-agency-enisa-testing-access-to-mythos-08a1d329) (Sep 10, 2026)
- [Anthropic says Mythos 5 is now in public beta in Claude Security for Enterprise users, and it is working with providers to embed Mythos 5 in defensive tools](https://frontiernewswire.com/s/anthropic-says-mythos-5-is-now-in-public-beta-in-claude-security-for-d96ae5e9) (Aug 22, 2026)
- [Sources: ByteDance is pretraining an AI model with up to 10T parameters, roughly 3x larger than Kimi K3 and larger than the 8T estimate for Anthropic's Mythos 5 (Financial Times)](https://frontiernewswire.com/s/sources-bytedance-is-pretraining-an-ai-model-with-up-to-10t-parameters-e1043e5e) (Aug 7, 2026)

## Related

- [AI Safety](https://frontiernewswire.com/topics/ai-safety) (Topic)
- [Anthropic](https://frontiernewswire.com/companies/anthropic) (Company)
- [UK AI Security Institute](https://frontiernewswire.com/companies/uk-ai-security-institute) (Company)
- [GitHub](https://frontiernewswire.com/companies/github) (Company)
- [Moonshot AI](https://frontiernewswire.com/companies/moonshot-ai) (Company)
- [Mythos 5.1](https://frontiernewswire.com/models/mythos-5-1) (Model)
- [Kimi K3](https://frontiernewswire.com/models/kimi-k3) (Model)
- [ByteDance](https://frontiernewswire.com/companies/bytedance) (Company)

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