CVE-2026-108954: k2-fsa sherpa-onnx Offline Transducer Greedy Search Decoder offline-transducer-greedy-search-decoder.cc Decode buffer overflow
A vulnerability was found in k2-fsa sherpa-onnx up to 1.13.8. This issue affects the function OfflineTransducerGreedySearchDecoder::Decode of the file sherpa-onnx/csrc/offline-transducer-greedy-search-decoder.cc of the component Offline Transducer Greedy Search Decoder. The manipulation of the argument vocabsize results in buffer overflow. The attack can be launched remotely. The exploit has been made public and could be used. If only official model packs are used and they always keep metadata consistent with the joiner, the bug may not be reachable in normal supported usage. However, from a security and robustness standpoint, the code still contains the vulnerability because it trusts unvalidated model metadata and can be triggered by a malformed or tampered model pack.
Affected Software
Event History
Frequently Asked Questions
Who is most likely to be exposed to this issue?
Deployments that load malformed or tampered sherpa-onnx model packs are exposed, because the decoder trusts model metadata. Normal supported use may not reach the flaw when only official model packs are used and their metadata remains consistent with the joiner.
What does an attacker need to exploit the vulnerability?
An attacker needs to cause processing of a model pack with a manipulated vocab_size value. The issue can be launched remotely, requires no privileges, and requires user interaction according to the supplied severity vector.
What can be done if updating is not immediately possible?
Restrict model packs to official, trusted sources and ensure their metadata is consistent with the joiner. Do not load unvalidated, modified, or externally supplied model packs.
How can we determine whether our deployment may be affected?
Check whether sherpa-onnx is used at version 1.13.8 or earlier and whether the application accepts or loads model packs that could be tampered with or malformed. Review the model-loading path for control over metadata, particularly vocab_size.