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Mythos Breach Reveals 271 Firefox Fixes, New Exploits

4/26/2026

25 4 Full Breakdown

Summary

Story summary

Anthropic said on April 24 2026 unauthorized users accessed Mythos after a Mercur breach.
Anthropic limits Mythos to Project Glasswing for select tech companies.
Mozilla said on April 25 2026 Mythos helped patch 271 Firefox 150 vulnerabilities.
Tests released April 7 showed Mythos chained four bugs into an exploit that escaped OS sandboxes.
Researchers say Mythos can turn flaws into Linux privilege escalations and a FreeBSD NFS remote-code exploit.

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Story summary

Anthropic said on April 24 2026 unauthorized users accessed Mythos after a Mercur breach.
Anthropic limits Mythos to Project Glasswing for select tech companies.
Mozilla said on April 25 2026 Mythos helped patch 271 Firefox 150 vulnerabilities.
Tests released April 7 showed Mythos chained four bugs into an exploit that escaped OS sandboxes.
Researchers say Mythos can turn flaws into Linux privilege escalations and a FreeBSD NFS remote-code exploit.