Uncontrolled Recursion in XGrammar - CVE-2026-25048
Published: April 24, 2026
Vulnerability identifier: #VU127412
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-25048
CWE-ID: CWE-674
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: mlc-ai
Affected software:
XGrammar
XGrammar
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled recursion in the grammar compiler when parsing a malicious grammar rule with deeply nested parentheses. A remote attacker can supply a specially crafted grammar input to cause a denial of service.
The issue can result in a segmentation fault, stack overflow, or memory exhaustion.
How to mitigate CVE-2026-25048
Install security update from vendor's website.