Cloudflare released a report stating that a GLM-5.3 flaw caused cross-tenant session leakage of 155 responses
Cloudflare、GLM-5.3の不具合によりテナント間のセッションで155件の応答が漏えいしたと発表
Cloudflare released an incident report on October 26, 2026: the GLM-5.3 model on its Workers AI platform suffered a cross-request KV cache leak, and 155 responses were mixed with data from other customers' sessions. The issue was reported by Knostic researcher Gadi Evron via HackerOne on September 8, 2026, and affected the service provided as @cf/zai-org/glm-5.3 since the model went live on August 27; Cloudflare fixed it and restored the model on September 9, stating that no evidence of deliberate abuse was found and that other Workers AI models were unaffected. Cloudflare has expanded the prefill KV pool to approximately 2.04 million tokens and deployed an engine patch; the relevant fixes have been merged into SGLang v0.5.20 through v0.5.22, and the company recommends that all SGLang operators upgrade to v0.5.22 or higher.
The report reconstructs the root cause of the cross-tenant leak caused by the mismatch between KV cache pool capacity and context window combined with an engine flaw; teams operating SGLang in disaggregated mode can check themselves against its recommendations.