CVE-2026-61769

NVIDIA's NeMo Megatron Bridge, a framework used to build and scale large language model training workflows, contains a CWE-502 deserialization-of-untrusted-data vulnerability. The flaw is triggered when the software deserializes untrusted data; per the CVSS vector the attack is local (AV:L), requires only low privileges (PR:L), involves no user interaction, and has low attack complexity, meaning an attacker or malicious process already running with limited rights on the machine can trigger it. A successful exploit could let the attacker execute code, tamper with data, or disclose sensitive information, with high impact on confidentiality, integrity, and availability (CVSS 3.1: 7.8). Affected users are teams running Megatron Bridge in ML development or training environments, especially on shared workstations or multi-tenant GPU clusters and wherever untrusted serialized inputs such as third-party checkpoints or data files are processed; the disclosure does not specify affected or fixed versions. No public proof-of-concept, CISA KEV listing, or confirmed in-the-wild exploitation is known, and EPSS estimates only a 0.2% probability of exploitation within 30 days.

What to do: Inventory pip/conda environments for the Megatron Bridge package and update to the latest patched release once NVIDIA's advisory for CVE-2026-61769 identifies fixed versions. Because the attack vector is local with low privileges required, prioritize shared or multi-user training hosts and treat untrusted serialized inputs (e.g., third-party checkpoints or data files) with caution. Monitor NVIDIA PSIRT advisories for updated guidance and version information.