CVE-2026-25048
Published: 05 March 2026
Summary
CVE-2026-25048 is a high-severity Uncontrolled Recursion (CWE-674) vulnerability in Mlc-Ai Xgrammar. Its CVSS base score is 8.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 33.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 RA-5 (Vulnerability Monitoring and Scanning) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-25048 is a vulnerability in the xgrammar open-source library, which enables efficient, flexible, and portable structured generation. In versions prior to 0.1.32, processing multi-level nested syntax triggers a segmentation fault resulting in a core dump. The issue carries a CVSS 3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and maps to CWE-674 (Uncontrolled Recursion).
Attackers require only network access to exploit this vulnerability, with low attack complexity, no privileges, and no user interaction needed. Successful exploitation causes high-impact availability disruption through application crashes via segmentation faults, enabling denial-of-service attacks against systems using vulnerable xgrammar instances.
The vulnerability has been patched in xgrammar version 0.1.32. Security practitioners should upgrade to this version or later, as detailed in the project's GitHub release notes (https://github.com/mlc-ai/xgrammar/releases/tag/v0.1.32) and security advisory (https://github.com/mlc-ai/xgrammar/security/advisories/GHSA-7rgv-gqhr-fxg3).
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-9830
Vulnerability details
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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability triggers remote segfault via uncontrolled recursion in exposed xgrammar library, directly enabling application crash and availability denial through software exploitation.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mandates timely identification, testing, and installation of patches for vulnerabilities like CVE-2026-25048, preventing segmentation faults from uncontrolled recursion in xgrammar.
Requires vulnerability scanning to identify systems using vulnerable xgrammar versions prior to network-accessible DoS exploitation.
Ensures monitoring and dissemination of security advisories, such as the xgrammar GitHub advisory, to enable rapid awareness and patching of this CWE-674 vulnerability.