Denial Of Service (DoS)

xgrammar is vulnerable to Denial of Service DoS. The vulnerability is due to improper handling of multi-level nested syntax, which can trigger a segmentation fault and crash the application...

xgrammar vulnerable to DoS via multi-layer nesting

Summary The multi-level nested syntax caused a segmentation fault core dump. Details A trigger stack overflow or memory exhaustion was caused by constructing a malicious grammar rule containing 30,000 layers of nested parentheses. PoC !/usr/bin/env python3 """ XGrammar - Math Expression Generatio...

Denial Of Service (DoS)

xgrammar is vulnerable to Denial Of Service DoS. The vulnerability is due to a regression in the Earley parser, which causes excessive processing time for valid grammar inputs, allowing an attacker to exploit this inefficiency to trigger denial of service through resource exhaustion...

EUVD-2025-10549

Malicious code in bioql PyPI...

xgrammar vulnerable to denial of service by huge enum grammar

Summary 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. Details Full reproducer provider in the POC section. The resulting grammar...

Denial Of Service (DoS)

XGrammar is vulnerable to Denial Of Service DoS. The vulnerability is due to unbounded in-memory caching of compiled grammars, allows an attacker to exhaust system memory due to unbounded in-memory caching of compiled grammars...

GHSA-HF3C-WXG2-49Q9 vLLM vulnerable to Denial of Service by abusing xgrammar cache

Impact This report is to highlight a vulnerability in XGrammar, a library used by the structured output feature in vLLM. The XGrammar advisory is here: https://github.com/mlc-ai/xgrammar/security/advisories/GHSA-389x-67px-mjg3 The xgrammar library is the default backend used by vLLM to support...

CVE-2025-32381

A flaw was found in Xgrammar. This vulnerability allows a denial of service DoS via unbounded memory usage when handling a large number of unique grammar inputs from untrusted sources. Mitigation Mitigation for this issue is either not available or the currently available options do not meet the...

CVE-2025-32381 Denial of Service by abusing xgrammar unbounded cache in memory

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 maki...

CVE-2025-32381 Denial of Service by abusing xgrammar unbounded cache in memory

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 maki...

CVE-2025-32381

XGrammar (open-source library for structured generation) has a DoS in-memory cache vulnerability. Before version 0.1.18, an unbounded in-memory cache of compiled grammars can be filled by many unique inputs (e.g., numerous JSON schemas), exhausting host memory and causing denial of service. The i...

PT-2025-15757 · Xgrammar · Xgrammar

Name of the Vulnerable Software and Affected Versions: XGrammar versions prior to 0.1.18 Description: The issue concerns an unbounded cache for compiled grammars in memory, which can be exploited to cause a denial of service by filling up a host's memory. This can occur when a system using XGramm...