CVE-2025-32381
xgrammar Vulnerable to Denial of Service (DoS) by abusing unbounded cache in memory
Description
XGrammar is an open-source library for efficient, flexible, and portable structured generation. Prior to 0.1.18, Xgrammar includes a cache for compiled grammars to increase performance with repeated use of the same grammar. This cache is held in memory. Since the cache is unbounded, a system making use of xgrammar can be abused to fill up a host's memory and case a denial of service. For example, sending many small requests to an LLM inference server with unique JSON schemas would eventually cause this denial of service to occur. This vulnerability is fixed in 0.1.18.
How to fix CVE-2025-32381
To remediate CVE-2025-32381, upgrade the affected package to a fixed version below.
- —upgrade to 0.1.18 or later
- —upgrade to 0.1.18 or later
Is CVE-2025-32381 being exploited?
Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 0.1.18
- from 0, < 0.1.18
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |