Out-of-bounds read in XGrammar - #VU162998

Vulnerability details

The vulnerability allows an unauthenticated remote attacker to crash inference servers using XGrammar for regex constraints, causing denial of service.

The vulnerability exists due to an out-of-bounds read in XGrammar's regex-to-EBNF converter when null-terminated parsing of a regex beginning with a null byte produces an empty vector. An unauthenticated remote attacker can submit a single malformed regex through an exposed SGLang or vLLM API to terminate the host process.

Affected software

Remediation

External References

• https://github.com/mlc-ai/xgrammar/security/advisories/GHSA-ggf7-2pq3-j6pv
• https://github.com/mlc-ai/xgrammar/security/advisories/ghsa-m5hf-r6jr-m4q6

Related Security Bulletins

• Multiple vulnerabilities in XGrammar