CTranslate2 prior to version 4.8.1 contains a heap‑based buffer overflow in its binary model loader. The loader fails to validate the payload length against the allocated buffer size, allowing an attacker who supplies a malicious model file with an oversized payload to overwrite heap memory. This flaw is classified as CWE‑787 and can lead to a crash or arbitrary code execution.

OpenNMT CTranslate2 versions earlier than 4.8.1 are affected. Any system using a pre‑4.8.1 release that loads model files from an untrusted source is vulnerable. The vulnerability resides in the model loader component of the library.

The CVSS score of 8.5 indicates high severity. No EPSS score is available, so the current likelihood of exploitation is unknown, yet the failure to appear in the KEV catalog suggests no widespread exploitation has been observed yet. Attackers would need to supply a crafted model file, implying a local or remote execution scenario where the model loader is invoked. If untrusted models are processed, the risk of arbitrary code execution is significant.