GCVE-110-CERTCC-2026-369611

### Overview An out-of-bounds (OOB) memory access vulnerability involving unchecked array indexing has been identified in the `exllamav3_ext` compute unified device architecture (`CUDA`) extension. Successful exploitation can lead to an immediate denial of service or application instability. This vulnerability is tracked as CVE-2026-84286. ### Description An OOB memory access vulnerability exists in the `exllamav3_ext` module due to insufficient input validation. When the kernel parameter `K` is set to 0 in a crafted input, the extension generates a negative array index, resulting in a `CUDA` illegal memory access.s. The root cause is a missing bounds check in the kernel-table dispatch process. The checkpoint-derived block index (`cbi`) is used to access a fixed 24-entry array without confirming that either `K` or `cbi` fall within safe limits. ### Impact Primary impacts include Denial of Service (DoS) through process crashes and potential unstable execution states within applications utilizing the library. ### Solution The vendor has addressed this vulnerability in the main repository. Users are advised to update their installations or apply the fix from the merged pull request: https://github.com/turboderp-org/exllamav3/pull/310. ### Supply chain Downstream projects utilizing this library are indirectly exposed to this vulnerability. According to the `ExLlamaV3` Dependency Graph, there are 49 total dependencies currently tracking this repository. Notable downstream projects directly affected by this supply chain link include: `UnstableLlama` / `ezexl3` and `Ednaordinary` / `MawDiscord` Developers and maintainers of these dependent repositories are strongly encouraged to rebuild their packages against the patched version of `exllamav3_ext`. ### Acknowledgements The CERT Coordination Center (CERT/CC) thanks Nathan Keys (professor-moody) for discovering and responsibly reporting this vulnerability. This AI-assisted vulnerability note was prepared by Laurie Tyzenhaus.