CVE-2025-33248
Published: 24 March 2026
Summary
CVE-2025-33248 is a high-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Nvidia Megatron-Lm. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 19.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly remediates the deserialization of untrusted data vulnerability (CWE-502) in NVIDIA Megatron-LM's hybrid conversion script by applying vendor-provided patches.
Validates files loaded by the hybrid conversion script to ensure only trusted, properly formatted data is deserialized, blocking maliciously crafted inputs.
Deploys malicious code detection and prevention tools to identify and block arbitrary code execution resulting from successful deserialization exploits.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
CWE-502 deserialization of untrusted data in file-loading script directly enables client-side RCE upon malicious file load (T1203/T1204.002) and subsequent arbitrary command execution (T1059).
NVD Description
NVIDIA Megatron-LM contains a vulnerability in the hybrid conversion script where an Attacker may cause an RCE by convincing a user to load a maliciously crafted file. A successful exploit of this vulnerability may lead to code execution, escalation of…
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privileges, information disclosure, and data tampering.
Deeper analysisAI
CVE-2025-33248 is a vulnerability in the hybrid conversion script of NVIDIA Megatron-LM, an open-source framework for training large language models. The issue, classified as CWE-502 (Deserialization of Untrusted Data), enables an attacker to achieve remote code execution (RCE) by convincing a user to load a maliciously crafted file. It carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high confidentiality, integrity, and availability impacts.
A local attacker with low privileges can exploit this vulnerability with low complexity and no additional user interaction beyond the initial file load. Successful exploitation allows arbitrary code execution on the host system, potentially leading to privilege escalation, information disclosure, and data tampering.
Advisories providing mitigation guidance and patch details are available from the National Vulnerability Database (https://nvd.nist.gov/vuln/detail/CVE-2025-33248), NVIDIA (https://nvidia.custhelp.com/app/answers/detail/a_id/5769), and CVE.org (https://www.cve.org/CVERecord?id=CVE-2025-33248). Security practitioners using Megatron-LM should consult these for updates, as the vulnerability was published on 2026-03-24.
Details
- CWE(s)