Episode Details

TL;DR: Anthropic restricted access to Claude Mythos Preview, citing a major leap in vulnerability discovery and exploitation capability. I review the 3 most common arguments from skeptics: (1) AISLE Security's paper showing cheaper models can identify the same bugs as Mythos, (2) benchmark comparisons showing GPT-5.5 performs comparably, and (3) Mythos finding only one low-severity bug in the cURL project.

• On most cyber capabilities: the skeptics are right. Mythos isn’t dramatically ahead of GPT-5.5, and GPT-5.5 is more cost-efficient for most use cases.
• On vulnerability discovery and exploitation capabilities specifically: the skeptics are wrong, or at least overreaching. AISLE Security's results don’t replicate when models are tested under similar conditions (Ex: Semgrep's experiment), and benchmarks designed to actually measure vulnerability discovery and exploitation skills (XBOW AI, ExploitBench) show Mythos substantially ahead.
• The cURL result is real but not decisive: Firefox and Palo Alto Networks have reported the opposite pattern. More data is needed before we can draw a definitive conclusion.

(For context, my background is in penetration testing and bug bounty hunting, mostly specializing in web security, secure code review, and cloud security.)

AI has been measurably accelerating vulnerability research. The volume of reported software vulnerabilities continues to [...]

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Outline:

(04:04) #1 AISLE Security's Paper

(10:10) #2 Mythos vs. GPT 5.5 Benchmark Performance

(17:07) #3 Only 1 Vulnerability Found in cURL

(20:12) Conclusion

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First published:
May 23rd, 2026

Source:
https://forum.effectivealtruism.org/posts/8yztpbjuPkyXsmA6n/are-mythos-cyber-capabilities-overstated-yes-and-no

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Narrated by TYPE III AUDIO.

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