CVE-2026-61764

NVIDIA Megatron Bridge contains a deserialization flaw (CWE-502) in which the framework processes untrusted serialized data without adequate validation. According to the CVSS vector (AV:L/PR:L/UI:N), exploitation requires a local attacker who already has low privileges on the host and does not require user interaction, such as when the framework deserializes data supplied by a local user or process. A successful exploit could allow the attacker to execute code, tamper with data, or disclose information on the affected system. Users and organizations running Megatron Bridge in LLM training or fine-tuning environments on NVIDIA systems are affected. No public proof-of-concept, KEV listing, or known in-the-wild exploitation exists, and EPSS estimates only a 0.3% chance of exploitation within 30 days.

What to do: Check NVIDIA's security bulletin (PSIRT) for this CVE to identify affected version ranges and upgrade to the fixed release when available. Until patched, avoid deserializing untrusted or externally supplied data (such as third-party checkpoints or serialized state) with Megatron Bridge and limit low-privilege local access to hosts running it. Ops teams should prioritize environments where untrusted training artifacts are ingested on shared or multi-user machines.