CVE-2025-32381

Denial of Service by abusing xgrammar unbounded cache in memory

Published Apr 9, 2025 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2025-10549 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.
Github GHSA Github GHSA GHSA-389x-67px-mjg3 xgrammar Vulnerable to Denial of Service (DoS) by abusing unbounded cache in memory
History
Type Values Removed Values Added
First Time appeared Mlc-ai
Mlc-ai xgrammar
CPEs cpe:2.3:a:mlc-ai:xgrammar:*:*:*:*:*:*:*:*
Vendors & Products Mlc-ai
Mlc-ai xgrammar
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Denial of Service by abusing xgrammar unbounded cache in memory
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Apr 9, 2025, 8:43 PM
Reserved
Apr 6, 2025, 7:46 PM
Status
Analyzed
Published
Apr 9, 2025, 4:15 PM
Modified
Jun 17, 2026, 9:11 AM
Severity
Moderate
Public date
Apr 9, 2025, 1:08 PM