Zhipu launches flagship model GLM-5.3 as China seeks Mythos-level edge in cyber defence
Company says GLM-5.3 outperformed leading US systems in cybersecurity tests, beating Anthropic’s Mythos 5 and OpenAI’s GPT-5.6 on CyberGym
Chinese artificial intelligence firm Zhipu, also known as Z.ai, has unveiled its flagship GLM-5.3 model, saying it beat Anthropic’s frontier Mythos 5 model in a key cybersecurity test, as China races to counter Western advances in AI defence.
Beijing-based Zhipu said GLM-5.3 achieved a success rate of 84.5 per cent on CyberGym, a benchmark that measures whether models can identify and validate security flaws from source code.
That was above Anthropic’s Mythos at 83.8 per cent and OpenAI’s GPT-5.6 Sol at 83.6 per cent, according to Zhipu.
However, the Chinese model did not match those foreign systems on ExploitBench, which gauges how far AI models climb the exploitation ladder. Its score of 54.4 per cent trailed Mythos’ 78 per cent and GPT-5.6 Sol’s 76.5 per cent.
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Zhipu said it had tested the model with security teams in China against real-world codebases, identifying 2,436 vulnerabilities across 269 projects after expert review. Of those, 1,097 were rated medium to high severity, according to the company.