vLLM: ReDoS via structured_outputs.regex compiled without timeout in xgrammar and outlines backends

Summary The structuredoutputs.regex API parameter passes a user-supplied regex string directly to grammar compiler backends with no compilation timeout. In the xgrammar backend, the string reaches compileregex with no guard. In the outlines backend, validateregexisbuildable blocks structural issu...

GHSA-RWXX-MRJM-WC2M vLLM: ReDoS via structured_outputs.regex compiled without timeout in xgrammar and outlines backends

Summary The structuredoutputs.regex API parameter passes a user-supplied regex string directly to grammar compiler backends with no compilation timeout. In the xgrammar backend, the string reaches compileregex with no guard. In the outlines backend, validateregexisbuildable blocks structural issu...

xgrammar vulnerable to denial of service by huge enum grammar

SummaryProvided 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. DetailsFull reproducer provider in the POC section. The resulting grammar i...

PYSEC-2026-2054 XGrammar affected by Denial of Service by infinite recursion grammars

Summary This issue: http://github.com/mlc-ai/xgrammar/issues/250 should have it's own security advisory. Since several tools accept and pass user supplied grammars to xgrammar, and it is so easy to trigger it seems like a High...

XGrammar affected by Denial of Service by infinite recursion grammars

SummaryThis issue: http://github.com/mlc-ai/xgrammar/issues/250 should have it's own security advisory. Since several tools accept and pass user supplied grammars to xgrammar, and it is so easy to trigger it seems like a High...

CVE-2026-55574 vLLM: ReDoS via structured_outputs.regex compiled without timeout in xgrammar and outlines backends

vLLM is a high-throughput and memory-efficient inference and serving engine for LLMs. Prior to 0.24.0, the structuredoutputs.regex API parameter passes a user-supplied regular expression string directly to the grammar compiler backends with no compilation timeout; in the xgrammar backend the stri...

CVE-2026-55574 vLLM: ReDoS via structured_outputs.regex compiled without timeout in xgrammar and outlines backends

vLLM is a high-throughput and memory-efficient inference and serving engine for LLMs. Prior to 0.24.0, the structuredoutputs.regex API parameter passes a user-supplied regular expression string directly to the grammar compiler backends with no compilation timeout; in the xgrammar backend the stri...

CVE-2026-55574 vLLM: ReDoS via structured_outputs.regex compiled without timeout in xgrammar and outlines backends

vLLM is a high-throughput and memory-efficient inference and serving engine for LLMs. Prior to 0.24.0, the structuredoutputs.regex API parameter passes a user-supplied regular expression string directly to the grammar compiler backends with no compilation timeout; in the xgrammar backend the stri...

CVE-2026-55574: Inefficient Regular Expression Complexity

vLLM is a high-throughput and memory-efficient inference and serving engine for LLMs. Prior to 0.24.0, the structuredoutputs.regex API parameter passes a user-supplied regular expression string directly to the grammar compiler backends with no compilation timeout; in the xgrammar backend the stri...

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...

Uncontrolled Recursion

Overview xgrammar is an Efficient, Flexible and Portable Structured Generation Affected versions of this package are vulnerable to Uncontrolled Recursion through the handling of multi-level nested grammar rules. An attacker can cause a segmentation fault and crash the application by submitting...

GHSA-7RGV-GQHR-FXG3 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...

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...

PYSEC-2026-2322

xgrammar is an open-source library for efficient, flexible, and portable structured generation. Prior to version 0.1.32, the multi-level nested syntax caused a segmentation fault core dumped. This issue has been patched in version 0.1.32...

CVE-2026-25048

xgrammar is an open-source library for efficient, flexible, and portable structured generation. Prior to version 0.1.32, the multi-level nested syntax caused a segmentation fault core dumped. This issue has been patched in version 0.1.32...

CVE-2026-25048 xgrammar: Multi-layer nesting causes DoS

xgrammar is an open-source library for efficient, flexible, and portable structured generation. Prior to version 0.1.32, the multi-level nested syntax caused a segmentation fault core dumped. This issue has been patched in version 0.1.32...

CVE-2026-25048

xgrammar is an open-source library for efficient, flexible, and portable structured generation. Prior to version 0.1.32, the multi-level nested syntax caused a segmentation fault core dumped. This issue has been patched in version 0.1.32...

CVE-2026-25048 xgrammar: Multi-layer nesting causes DoS

xgrammar is an open-source library for efficient, flexible, and portable structured generation. Prior to version 0.1.32, the multi-level nested syntax caused a segmentation fault core dumped. This issue has been patched in version 0.1.32...

CVE-2026-25048 xgrammar: Multi-layer nesting causes DoS

xgrammar is an open-source library for efficient, flexible, and portable structured generation. Prior to version 0.1.32, the multi-level nested syntax caused a segmentation fault core dumped. This issue has been patched in version 0.1.32...

CVE-2026-25048

CVE-2026-25048 affects xgrammar prior to v0.1.32, where a multi-level nested syntax causes a segmentation fault (core dumped). The issue is fixed in v0.1.32. According to the provided metrics, the exposure is high impact to availability, with no impact on confidentiality or integrity. No exploit ...