The vulnerability is a buffer overflow in the OfflineTransducerGreedySearchDecoder::Decode function of sherpa-onnx, triggered by manipulating the vocab_size argument in model metadata. This overflow can overwrite adjacent memory, leading to arbitrary code execution or denial of service. The weakness aligns with CWE-119 and CWE-120.

Affected systems are installations of k2‑fsa sherpa‑onnx up to version 1.13.8. The function resides in the Offline Transducer Greedy Search Decoder component. The issue is present in all releases prior to 1.13.8, regardless of operating system, as it is a library‑level flaw.

The CVSS score of 5.3 indicates moderate severity, and the EPSS score is unavailable, so the exploitation probability is unclear. The vulnerability is not listed in the CISA KEV catalog. Attack can be launched remotely by supplying a malformed or tampered model pack; the exploit has been made public, but the risk is mitigated if only official model packs that keep metadata consistent are used. From a security standpoint, however, the code trusts unvalidated metadata and can still be triggered.