🛡️ CVE-2025-32381 — xgrammar

🟡 CVSS 6.5 — Medium ✅ No Known Exploit CWE-770 OSV
6.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

xgrammar Vulnerable to Denial of Service (DoS) by abusing unbounded cache in memory

Summary

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.

Details

The fix is to add a limit to the cache size. This was done in https://github.com/mlc-ai/xgrammar/pull/243

An example of making use of the new cache size limit can be found in vLLM here: https://github.com/vllm-project/vllm/pull/16283

Impact

Any system making use of Xgrammar and taking requests as input from potentially untrusted parties would be vulnerable to this denial of service issue.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Weakness class

CVE-2025-32381 is classified as CWE-770: Allocation of Resources Without Limits. Resources are allocated on request with no cap, so a client can exhaust them.

Affected software

CVE-2025-32381 is recorded against 1 package.

  • xgrammar (fixed in 0.1.18)

Timeline and source

Published on 9 April 2025 and last revised on 7 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from OSV.

References

github.com (Web)
nvd.nist.gov (Advisory)
github.com (Web)
github.com (Web)
github.com (Package)
github.com (Web)

Details

Severity MEDIUM
CVSS Score 6.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE CWE-770
Public Exploit ✅ No
Source OSV
Published 2025-04-09
Updated 2026-08-12
Modified 2026-08-07

Affected Packages

Software From version Fixed in
xgrammar — 0.1.18

Similar Threats

Vulnerability Monitoring

Track new vulnerabilities in xgrammar

CVE-2025-32381 is rated CVSS 6.5 Medium. BotEraser monitors your WordPress installation and notifies you when software you use appears in our vulnerability database.

Set Up Free Alerts →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.