Z.ai Unveils GLM-5.3 AI Model, Scoring 84.5% on CyberGym in China's Race to Close the Gap

China's Z.ai says new model nears Anthropic's Mythos 5 in cyber-defence tests

BEIJING, Aug 14 (Reuters) - Chinese AI startup Z.ai said on Friday its open-source GLM-5.3 model had neared Anthropic's restricted Mythos 5 in identifying software vulnerabilities, bolstering the credentials of a Chinese AI challenger gaining traction among Western developers. Z.ai said GLM-5.3 scored 84.5% on CyberGym, a test of whether a model can review code, identify security flaws and confirm that they are real. That was slightly higher than the 83.8% it reported for Mythos 5. The results have not been independently verified. GLM-5.3 lagged behind Mythos 5 in converting discovered flaws into working attacks -- a standard part of defensive security research. Z.ai said its model scored 54.4% on the ExploitBench test of this capability, versus ⁠78.0% for Mythos 5. In a separate timed test, Z.ai said GLM-5.3 completed 105 attack-development tasks in two hours and 130 in six hours. Mythos 5 completed 181 and 247 tasks, respectively. Anthropic has made Mythos, a version of its Claude Fable 5 model with cybersecurity safeguards removed, available only to vetted organisations. Such controls reflect concern that AI systems capable of finding and exploiting software flaws can assist defenders but may also lower barriers for attackers. Z.ai said it would release GLM-5.3 publicly in about two weeks after completing security assessments and strengthening its safeguards. Its most sensitive cybersecurity functions would be available only to verified users through a "trusted access" programme, it said. The company said it had added several layers of protection to GLM-5.3, including systems to screen risky requests, monitor the model's work and train it to reject malicious tasks. It said these were designed to distinguish harmful ⁠activity from legitimate uses such as fixing bugs, teaching cybersecurity or authorised security testing. But critics say those safeguards become harder to enforce once a model is released for others to download, alter or combine with outside tools. CHALLENGING CLOSED-SOURCE MYTHOS Z.ai framed the launch as a challenge to the restricted-access model represented by Mythos. It argued that advanced cyber-defence tools should be available to developers of open-source software and smaller security teams, rather than being controlled by a limited number of ⁠closed-model providers. It said it would begin an "Open Source Shield" initiative to audit selected open-source projects, provide model access for defensive work and add code-auditing functions to its ZCode programming product. Z.ai is not the first Chinese company to position a product as an answer to Mythos. Cybersecurity firm 360 said in June that its Tulongfeng ⁠vulnerability-discovery system had achieved Mythos-equivalent capabilities by combining AI models with security data and automated tools, though those claims were not independently verified. GLM-5.3 differs in that it is a general-purpose coding model that Z.ai says acquired cybersecurity capabilities through expanded post-training and reinforcement learning, rather than a ⁠purpose-built security system. The company said it used the same base model as GLM-5.2 but trained it in longer and more varied task environments. The launch builds on global interest in GLM-5.2, which gained attention in recent months among overseas developers for coding and agent capabilities that users and analysts said approached leading U.S. models but at a much lower cost. Reporting by Eduardo Baptista. Editing by Mark Potter Our Standards: The Thomson Reuters Trust Principles., opens new tab * Suggested Topics: * Cybersecurity Eduardo Baptista Thomson Reuters Eduardo Baptista is Chief Technology Correspondent, Greater China, for Reuters, based in Beijing. He covers artificial intelligence, semiconductors and emerging technologies. He holds a BA in History from the University of Cambridge.

China's Z.ai unveils GLM-5.3, claims chart-leading scores

GLM-5.3 scores 84.5pc on CyberGym, ahead of Anthropic's Mythos 5 and OpenAI's GPT-5.6 Sol. Chinese AI company Z.ai has unveiled its latest open-weights model - GLM-5.3 - whose performance, it says, rivals that of OpenAI and Anthropic newest frontier launches - marking the latest in the ever-escalating battle between US and Chinese companies for AI dominance. The new model makes a significant leap in capability compared to its predecessor GLM-5.2, which launched just months ago in June. GLM-5.3 is "much better" at complex coding and long-horizon tasks, Z.ai said, boasting a 50pc improvement from the older version in its in-house code benchmarks. The company plans to release GLM-5.3's weights in two weeks' time, after wrapping up safety evaluation and hardening. "[GLM-5.3] delivers markedly stronger agentic coding results than GLM-5.2 at every effort level while consuming fewer output tokens," Z.ai said. GLM-5.3 also proves significantly more capable at exploiting vulnerabilities, scoring 84.5pc on CyberGym, above Anthropic's Mythos 5 and OpenAI's GPT-5.6 Sol. "We expected this to make the model better at finding and reasoning about vulnerabilities. What surprised us was how quickly the capability continued to develop as training scaled," Z.ai said. Despite its lofty claims about the new model, the Hong Kong-listed company's shares slid nearly 4pc at market close today (14 August). "This firm remains on a completely unsustainable commercial footing," intelligence analyst Robert Lea told Bloomberg. "Rising agentic AI will drive Z.ai's inference costs and losses higher." Chinese-made models are increasingly offering models at par with its American counterparts at cheaper prices, in spite of the heavy constraints around chip exports into the country. Last month, Z.ai completed the construction of a data centre where has installed at least 10,000 Chinese-made chips to help develop its GLM line of models. Other frontier models from China, including Moonshot's latest Kimi model, DeepSeek's V4 models and Alibaba's Qwen series, have all ranked high in benchmarks. The Beijing-based start-up went public in January this year, raising funds at a market capitalisation of nearly $7bn. Shares at the company surged 2,000pc in June following the launch of GLM-5.2, taking Z.ai's valuation to $128bn. Though that has since fallen to $75bn. Don't miss out on the knowledge you need to succeed. Sign up for the Daily Brief, Silicon Republic's digest of need-to-know sci-tech news.

Zhipu's new AI model takes aim at OpenAI, Anthropic in China's race to close the gap

Chinese AI firm Z.ai has launched its new GLM-5.3 model. This release intensifies competition with OpenAI and Anthropic. The model offers improved coding capabilities and open access for developers. Chinese AI companies are narrowing the performance gap with US rivals. Z.ai aims to attract users with its permissive licensing approach. Chinese artificial intelligence company Z.ai, also known as Zhipu, has released the latest version of its flagship model, stepping up competition with US leaders OpenAI and Anthropic with a focus on stronger coding capabilities and open access. The Beijing-based company's new GLM-5.3 builds on the same roughly 700-billion-parameter base model as GLM-5.2, which was released in June, but is designed to deliver a significant improvement in coding and other capabilities. Also Read: China's Zhipu posts 132% rise in annual revenue on AI boom Z.ai plans to release the model's weights, the underlying parameters that allow developers to download, modify and customise an AI system, within two weeks. The company said benchmark results showed GLM-5.3 substantially outperforming its already well-regarded predecessor and approaching, and in some tests approaching, Anthropic's Fable 5. The release comes as Chinese AI companies accelerate efforts to challenge the dominance of US developers in increasingly capable large language models. San Francisco-based Anthropic and OpenAI remain widely regarded as having some of the industry's most capable models. But Chinese companies have increasingly narrowed the performance gap, while offering models at lower costs and, in several cases, making their weights openly available to developers. Moonshot AI's Kimi, DeepSeek's latest V4 models and Alibaba Group Holding's Qwen have all scored highly in AI benchmarks. Z.ai is seeking to build on that momentum with a permissive licence intended to attract developers and users to its models. China's AI challengers gain groundThe competitive landscape is also shifting on price. DeepSeek raised prices for its V4 Flash and Pro models by as much as fourfold on Thursday. Even after the increase, the blended price of V4 Pro remains below that of GLM-5.2, according to Artificial Analysis. The third-party evaluator gives DeepSeek's top model and GLM-5.2 an identical intelligence score of 53. Both trail Kimi K3 as well as US frontier models including Claude Fable 5 and OpenAI's GPT 5.6. Also Read: After Anthropic shutdown, China's Z. ai closes frontier gap as it plans dual listing For Z.ai, the improving performance of Chinese models comes alongside a rapidly expanding commercial footprint. The company is among China's AI pioneers and became the world's first large language model maker to go public. Its market value surged to $137 billion at its peak following the release of GLM-5.2, briefly overtaking Chinese internet companies including PDD Holdings and NetEase. The valuation has since fallen to about $80 billion, although that still represents roughly a tenfold increase from its January listing in Hong Kong. Z.ai has also been building out the computing infrastructure needed to support its models. The company completed a data centre with at least 10,000 Chinese-made chips for developing and deploying its GLM models, Bloomberg reported in July. Its annual recurring revenue, predictable yearly revenue generated from developers and businesses using its services, reached $1 billion in July, according to the report. The latest GLM release adds another contender to a rapidly evolving AI race in which Chinese developers are increasingly competing not only on model performance, but also on cost, accessibility and the ability to let developers build directly on their technology.

Zhipu's GLM-5.3 Matches Fable 5 On Coding Using Only Post-Training, And Stuns Fans By Unearthing A Vulnerability All The Way From 1981

Another day brings yet another impressive model from a China-based AI lab, with Zhipu's GLM-5.3 taking the center stage today after Meta's Muse Glimmer, NVIDIA's Nemotron 3.5 Lightning, DeepSeek's V4 Pro, and Google's Gemini 3.7 Flash dominated the airwaves earlier in the week. Zhipu's GLM-5.3 is primarily focused on coding and security, with impressive gains in relevant benchmarks, such as a ~1.5x gain on DeepSWE, a 6x gain on Terminal Bench 3.0, and an apex predator status on CyberGym The GLM-5.3 is distinctive in that it sports the same 743 billion parameters of its predecessor, with all of the gains in coding and cyber security coming from Zhipu's post-training post-training protocols. As such, GLM-5.3 has a score of 66.9 on DeepSWE vs. a score of 46.2 for GLM 5.2, and 69.7 for Anthropic's Mythos-class Fable 5. On Terminal Bench 3.0, GLM-5.3 achieves a score of 28.3 vs. 4.6 for GLM-5.2 and 33.7 for Fable 5. On CyberGym, GLM-5.3 is currently leading with a score of 84.5 vs. 83.8 for Fable 5 and 83.6 for GPT-5.6 Sol. Remember, all of these gains are solely the result of Zhipu's post-training process, which is an eminently impressive feat in and of itself. Zhipu has also published a ledger, disclosing 2,436 security findings across 269 open-source projects, of which 1,097 were Critical or High severity. Interestingly, the oldest vulnerability that GLM-5.3 found dated all the way back to 1981! What's more, these security exploits had evaded discovery for an average of 26.6 years. Finally, do note that Zhipu's next model will switch to a new architecture with 2x as many parameters, which suggests that the AI lab is now seriously gunning after Fable 5's lunch. The company will release the model weights for GLM-5.3 in a few days. Follow Wccftech on Google to get more of our news coverage in your feeds.