Zhipu AI releases GLM-5.3, claims it's the strongest open-weights coding model

Chinese AI startup Zhipu AI has released GLM-5.3. The model shares the same base as its predecessor, GLM-5.2, and all gains come from extended post-training alone. Zhipu says GLM-5.3 is the most powerful open-weights coding model, with the biggest jumps in agent-based tasks.

One area where top Chinese models like Kimi or Qwen still lag behind US frontier models is cybersecurity. Zhipu trained GLM-5.3 with data and environments built to find software vulnerabilities. According to Z.ai, the model "began to reason across multiple stages of exploitation, forming coherent plans for complete exploitation chains." Working with security teams in China, the company says it found 2,436 vulnerabilities across 269 projects, some up to 40 years old. The flaws are documented in a public registry.

GLM-5.3 is available now through the GLM Coding Plan and works with coding agents like ZCode, Claude Code, or OpenCode. The model weights are set to go open source in two weeks, once security reviews wrap up.

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