Anthropic says Zhipu's open-source GLM-5.3 nears Claude Mythos Preview on exploit capability

Anthropic says Zhipu's open-weight GLM-5.3 nearly matches Claude Mythos Preview at building exploits

Anthropic published an evaluation saying Zhipu's open-source GLM-5.3 comes close to its Claude Mythos Preview on exploit capability. The comparison puts a specific number on how far open models have closed the gap with frontier systems on offensive cyber tasks.

Why it matters: Anthropic and CAISI test data show the measured gap between open models and frontier models on cyberattack capability, plus concrete paths where safeguards were bypassed.