Cyber Resilience

CVE-2025-33248

Deserialization in Nvidia Megatron-Lm ≤ 0.15.3

Published
24 March 2026
Modified
25 March 2026
Patch / advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0021 11th percentile
Risk Priority 55 floored blend · peak EPSS

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 Exploit Public-Facing Application (T1190); ranked at the 11th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

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.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

privileges, information disclosure, and data tampering.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-24151Same product: Nvidia Megatron-Lm
CVE-2025-33247Same product: Nvidia Megatron-Lm
CVE-2026-24150Same product: Nvidia Megatron-Lm
CVE-2026-24152Same product: Nvidia Megatron-Lm
CVE-2025-23354Same product: Nvidia Megatron-Lm
CVE-2025-23353Same product: Nvidia Megatron-Lm
CVE-2025-23264Same product: Nvidia Megatron-Lm
CVE-2025-23305Same product: Nvidia Megatron-Lm
CVE-2025-23348Same product: Nvidia Megatron-Lm
CVE-2025-23306Same product: Nvidia Megatron-Lm

Affected Assets

nvidia
megatron-lm
≤ 0.15.3

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can uncover deserialization flaws before deployment.

Input validation directly stops deserialization of untrusted data by ensuring inputs are valid before processing.

Engineering principles such as safe deserialization and input sanitization structurally prevent the weakness from being introduced.

Integrity verification tools can detect malformed or tampered serialized data after the fact.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-02 none match
prevents

PR.PS-02 addresses only post-deployment updates/patching and cannot prevent introduction of unsafe deserialization code, yet it can remediate some instances when the flaw exists in outdated libraries or components.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing includes validation of deserialization routines and the use of untrusted data, reducing the likelihood that unsafe object reconstruction will be deployed.

prevents

Requiring vetted libraries, regular updates and SAST before release reduces the likelihood that deserialization logic will accept and act on attacker-controlled serialized objects.

finds

Regular scanning of third-party libraries and timely patching reduce the likelihood that unsafe deserialization vulnerabilities remain active.

none

Mandatory malware scanning of data received over networks or storage media intercepts malicious serialized payloads before they are deserialized by the target application.

References