CVE-2025-33241: 
NixOS vulnerability analysis and mitigation

CVE-2025-33241 is a deserialization of untrusted data vulnerability in the NVIDIA NeMo Framework that allows an attacker to achieve remote code execution by loading a maliciously crafted file. It affects all versions of NVIDIA NeMo prior to 2.6.1. The vulnerability was published on February 18, 2026, with an initial NVD analysis completed on February 20, 2026. It carries a CVSS v3.1 base score of 7.8 (High), as assigned by NVIDIA Corporation (NVIDIA Advisory, Red Hat CVE).

The root cause is classified as CWE-502 (Deserialization of Untrusted Data), where the NeMo Framework fails to safely handle file loading operations, allowing attacker-controlled serialized data to be deserialized and executed. The attack vector is local, requiring low privileges and no user interaction, meaning an attacker with a foothold on the system can trigger exploitation by supplying a crafted file to the framework's file-loading functionality. This maps to CAPEC-586 (Object Injection), where malicious objects embedded in serialized payloads are instantiated during deserialization, leading to arbitrary code execution (NVIDIA Advisory, Red Hat CVE).

Successful exploitation can result in full system compromise, including arbitrary code execution, privilege escalation, information disclosure, and data tampering. The vulnerability provides high impact across all three security pillars — confidentiality, integrity, and availability — on the affected host. Given NeMo's role as an AI/ML framework often handling sensitive model data and training pipelines, exploitation could expose proprietary models, training datasets, or credentials stored on the system (NVIDIA Advisory, Red Hat CVE).

As of the time of disclosure, there is no public proof-of-concept exploit and no evidence of in-the-wild exploitation (Red Hat CVE). The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. The EPSS score is approximately 0.263%, indicating a low probability of exploitation in the near term. The local attack vector and low-privilege requirement reduce the immediate risk compared to remotely exploitable vulnerabilities, but the high impact upon successful exploitation warrants prompt patching.

1. Initial Access: Obtain local access to a system running NVIDIA NeMo Framework versions prior to 2.6.1 with at least low-level user privileges.
2. Craft Malicious File: Prepare a serialized payload (e.g., using Python's pickle or a similar serialization format supported by NeMo) that embeds malicious object definitions designed to execute arbitrary commands upon deserialization.
3. Deliver the File: Place or supply the crafted file to a location or input path that the NeMo Framework will process during a file-loading operation (e.g., model checkpoint loading, configuration file parsing).
4. Trigger Deserialization: Invoke the NeMo Framework's file-loading functionality — either directly or by manipulating a pipeline that automatically loads the file — causing the malicious serialized object to be deserialized.
5. Achieve Code Execution: The deserialized payload executes arbitrary code in the context of the NeMo process, potentially enabling privilege escalation, data exfiltration, or persistence on the host (NVIDIA Advisory).

• Process: Unexpected child processes spawned by the NeMo Python process (e.g., bash, sh, curl, wget, python) that are not part of normal ML training or inference workflows.
• File System: Presence of unfamiliar or recently modified serialized files (e.g., .pkl, .pt, .ckpt) in NeMo model or checkpoint directories; new scripts or binaries dropped in writable directories accessible by the NeMo service account.
• Logs: Python runtime errors or tracebacks related to deserialization (e.g., pickle, torch.load) in NeMo application logs; unexpected import of unusual modules during file loading.
• Network: Outbound connections from the NeMo process to unknown external IP addresses or domains, particularly following a file-load operation, which may indicate a reverse shell or data exfiltration attempt.

NVIDIA has released NeMo Framework version 2.6.1 to address this vulnerability; users should upgrade immediately (NVIDIA Advisory). As interim mitigations, restrict local access to systems running vulnerable NeMo versions and implement strict access controls on who can supply or modify files loaded by the framework. Avoid loading serialized files (e.g., model checkpoints) from untrusted or unverified sources until the patch is applied.

The vulnerability was noted by automated threat intelligence aggregators and security feeds shortly after disclosure, with coverage on platforms such as Vulners, VulDB, and CVEFeed. A post on Bluesky by The Hacker Wire highlighted the vulnerability to the security community. No significant vendor statements beyond the official NVIDIA security bulletin, nor notable independent researcher commentary, have been identified at this time (NVIDIA Advisory).