From the source

GLM-5.3

Model update

Z.ai releases GLM-5.3, an update to its model series, with improved coding capabilities (50% gain over GLM-5.2 on Z.ai Code Bench) and emergent cybersecurity capabilities matching Mythos 5 in white-box code review and vulnerability discovery (identified 2,436 vulnerabilities on real-world targets).

From the source
GLM-5.3 delivers a significant improvement in coding capabilities, achieving a 50% gain over GLM-5.2 on Z.ai Code Bench and reaching state-of-the-art (SOTA) performance among open-source models on public benchmarks, including Terminal Bench 3.0.
docs.z.ai