CTranslate2 CVE-2026-102566 & CVE-2026-102567 — Heap Overflow in AI Model Loader

Two memory-safety vulnerabilities in CTranslate2, the inference engine behind Whisper and OpenNMT, were disclosed on September 29, 2026, and fixed in version 4.8.1. CVE-2026-102566 (CVSS 7.8) is a heap buffer overflow in the binary model loader that can lead to arbitrary code execution, while CVE-2026-102567 (CVSS 6.1) is an out-of-bounds read during string field deserialization that can crash the loader or disclose adjacent heap memory, potentially exposing user data in AI-as-a-Service deployments. Both flaws require only that a victim load a malicious model file, and the vulnerabilities were reported by Chegne Eu Joe via VulnCheck.

A malicious model file is enough to corrupt memory in CTranslate2 — the inference engine behind Whisper, OpenNMT, and dozens of AI applications. Two memory-safety flaws disclosed September 29, 2026. Both affect CTranslate2 before 4.8.1. Both are fixed in 4.8.1. | CVE | CVSS | Type | Component | |---|---|---|---| | CVE-2026-102566 | 7.8 | CWE-120 Heap Buffer Overflow | Binary model loader | | CVE-2026-102567 | 6.1 | CWE-125 Out-of-Bounds Read | String field deserialization | CVE-2026-102566 — The binary model loader reads a payload length from the model file but never validates it against the allocated heap buffer before copying. Craft a model file with an inflated length field, write past the heap boundary, corrupt adjacent memory structures. Arbitrary code execution. CVE-2026-102567 — String fields in model files are deserialized without verifying a null terminator exists. The loader reads past the buffer into adjacent heap memory — crash or memory disclosure. In AI-as-a-Service deployments this could expose user data stored nearby. CTranslate2 powers Whisper, OpenNMT, and countless custom inference services. Model files get pulled from Hugging Face, GitHub releases, internal registries — often automatically in CI/CD pipelines. The attack surface is: anyone who can put a model file in front of your inference server. No public PoC exists yet. The attack requires only that a victim loads the malicious file. Upgrade to CTranslate2 4.8.1 immediately. Until patched: Vulnerabilities reported by Chegne Eu Joe via VulnCheck. Full analysis with CVSS vectors, CWE classifications, and mitigation checklist: CTranslate2 CVE-2026-102566 & CVE-2026-102567 https://threataft.com/articles/ctranslate2-cve-2026-102566-102567-model-loader Originally published at ThreatAft https://threataft.com