CVE-2026-24242: Nvidia Nemo Megatron Bridge SSRF Flaw

CVE-2026-24242 Overview

CVE-2026-24242 affects NVIDIA Megatron Bridge for Linux. The vulnerability allows an attacker to trigger server-side request forgery (SSRF) through the affected component [CWE-918]. Successful exploitation can lead to information disclosure, along with impacts to integrity and availability of the system.

The CVSS vector CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H indicates a local attack vector requiring user interaction. NVIDIA published details through its product security repository on GitHub. No public proof-of-concept exploit or CISA Known Exploited Vulnerabilities listing exists at the time of publication.

Critical Impact
Exploitation of CVE-2026-24242 can force the Megatron Bridge process to issue attacker-controlled requests, exposing internal resources and sensitive data.

Affected Products

NVIDIA NeMo Megatron Bridge for Linux (all versions prior to the vendor's fix)
Linux kernel-based hosts running the affected Megatron Bridge software
AI/ML training environments integrating NeMo Megatron Bridge components

Discovery Timeline

2026-07-01 - CVE-2026-24242 published to NVD
2026-07-02 - Last updated in NVD database

Technical Details for CVE-2026-24242

Vulnerability Analysis

CVE-2026-24242 is a server-side request forgery flaw in NVIDIA Megatron Bridge for Linux, classified under [CWE-918]. The bridge component accepts input that is used to construct outbound network requests without sufficient validation of the destination. An attacker with local access, combined with user interaction, can supply a crafted resource identifier that redirects those requests to unintended internal or external endpoints.

Because NeMo Megatron Bridge often runs in environments that host large language model training workloads, the process typically has network reachability to model registries, storage buckets, and metadata services. An SSRF primitive in this context can be leveraged to retrieve cloud instance metadata, query internal APIs, or exfiltrate model artifacts. The advisory notes high impact to confidentiality, integrity, and availability.

Root Cause

The root cause is insufficient validation of user-supplied URLs or request targets before the Megatron Bridge process issues outbound HTTP or file-fetch operations. The application trusts input that influences request destinations, allowing schemes, hosts, or paths outside the intended scope. This aligns with the [CWE-918] pattern of failing to constrain a resource identifier to an allowlist of safe endpoints.

Attack Vector

Exploitation requires local access to the system running Megatron Bridge and interaction from a user who executes or accepts an attacker-supplied artifact, such as a configuration file, dataset reference, or model URL. Once the crafted input is processed, the bridge issues the forged request server-side. The attacker can then read responses returned to the process, enabling disclosure of internal service data or credentials returned by metadata endpoints. Technical details are documented in the NVIDIA product security advisory and the NVD entry for CVE-2026-24242.

Detection Methods for CVE-2026-24242

Indicators of Compromise

Outbound HTTP requests from the Megatron Bridge process to internal RFC1918 addresses, localhost, or cloud metadata endpoints such as 169.254.169.254.
Unexpected DNS lookups originating from the bridge host for attacker-controlled or non-approved domains.
Configuration files, dataset manifests, or model references containing URLs that do not match the organization's approved artifact registries.

Detection Strategies

Baseline the network destinations Megatron Bridge normally contacts and alert on deviations, especially requests to metadata services or internal management interfaces.
Inspect Megatron Bridge input files and job submissions for URL schemes other than the approved set (for example, block file://, gopher://, and unexpected http:// internal hosts).
Correlate process telemetry showing the bridge binary issuing network connections shortly after ingesting new configuration or dataset artifacts.

Monitoring Recommendations

Log all outbound connections from AI/ML training hosts and forward them to a centralized analytics tier for review.
Enable audit logging for changes to Megatron Bridge configuration files and model registry references.
Monitor cloud instance metadata service (IMDS) access patterns and enforce IMDSv2 to require session tokens.

How to Mitigate CVE-2026-24242

Immediate Actions Required

Apply the fixed version of NVIDIA NeMo Megatron Bridge referenced in the NVIDIA product security advisory as soon as it is available in your environment.
Restrict local user access to hosts running Megatron Bridge, since exploitation requires local access and user interaction.
Review recent Megatron Bridge job submissions and configuration changes for suspicious URLs or resource references.

Patch Information

NVIDIA published this issue through its product-security GitHub repository. Refer to the NVIDIA advisory for CVE-2026-24242 and the CVE.org record for the fixed release identifiers and upgrade instructions specific to your deployment.

Workarounds

Enforce egress network policy on Megatron Bridge hosts, limiting outbound traffic to an allowlist of approved model registries and storage endpoints.
Block access from the bridge process to cloud metadata endpoints (for example, deny traffic to 169.254.169.254) and require IMDSv2 where applicable.
Validate and sanitize all user-provided URLs, dataset paths, and model references before they are consumed by Megatron Bridge jobs.

bash

# Example egress restriction: block Megatron Bridge host from reaching cloud metadata
iptables -A OUTPUT -m owner --uid-owner megatron -d 169.254.169.254 -j DROP
iptables -A OUTPUT -m owner --uid-owner megatron -d 127.0.0.0/8 -j DROP

# Require IMDSv2 (AWS example) to reduce SSRF-to-credential-theft risk
aws ec2 modify-instance-metadata-options \
  --instance-id i-0123456789abcdef0 \
  --http-tokens required \
  --http-endpoint enabled