CVE-2025-58446: xgrammar vulnerable to denial of service by huge enum grammar

September 5, 2025 (updated November 10, 2025)

Provided grammar, would fit in a context window of most of the models, but takes minutes to process in 0.1.23. In testing with 0.1.16 the parser worked fine so this seems to be a regression caused by Earley parser.

References

github.com/advisories/GHSA-9q5r-wfvf-rr7f
github.com/mlc-ai/xgrammar
github.com/mlc-ai/xgrammar/commit/ced69c3ad2f8f61b516cc278a342e7c644383e27
github.com/mlc-ai/xgrammar/security/advisories/GHSA-9q5r-wfvf-rr7f
nvd.nist.gov/vuln/detail/CVE-2025-58446

Code Behaviors & Features

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