#VU118091 Uncontrolled recursion in XGrammar - CVE-2025-57809

Vulnerability identifier: #VU118091

Vulnerability risk: Medium

CVSSv4.0: 4.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-57809

CWE-ID: CWE-674

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
XGrammar
Universal components / Libraries / Libraries used by multiple products

Vendor: mlc-ai

Description

The vulnerability allows a remote user to perform a denial of service (DoS) attack.

The vulnerability exists due to uncontrolled recursion. A remote user can pass specially crafted input to the application and perform a denial of service attack. 

Mitigation
Install updates from vendor's website.

Vulnerable software versions

XGrammar: 0.1.0 - 0.1.20

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External links
https://github.com/mlc-ai/xgrammar/commit/b943feacb5a1caf4d39de8ec3bf7c7ce066dcee5
https://github.com/mlc-ai/xgrammar/issues/250
https://github.com/mlc-ai/xgrammar/security/advisories/GHSA-5cmr-4px5-23pc

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.