CVE-2026-47617 Overview
CVE-2026-47617 is a server-side request forgery (SSRF) vulnerability in NVIDIA Dynamo for Linux. The flaw resides in the multimodal media fetcher component, which resolves and retrieves remote media resources. An attacker can abuse DNS rebinding to bypass address validation and coerce the fetcher into issuing requests to unintended internal destinations. Successful exploitation may lead to information disclosure from resources reachable by the Dynamo host. The issue is tracked under CWE-918 and is reachable over the network without authentication or user interaction.
Critical Impact
An unauthenticated remote attacker can pivot the Dynamo media fetcher to internal services, exposing sensitive data accessible from the server.
Affected Products
- NVIDIA Dynamo for Linux (multimodal media fetcher component)
- See the NVIDIA product security advisory 5842 for exact affected versions
- Deployments exposing the Dynamo media-fetch endpoint to untrusted networks
Discovery Timeline
- 2026-08-04 - CVE-2026-47617 published to NVD
- 2026-08-06 - Last updated in NVD database
Technical Details for CVE-2026-47617
Vulnerability Analysis
NVIDIA Dynamo accepts URLs pointing at multimodal media (images, audio, or video) and fetches them for downstream inference tasks. The fetcher validates the target hostname before dispatching the request. An attacker controlling authoritative DNS for a hostname can return a public IP address during validation, then swap the response to an internal address such as 127.0.0.1, 169.254.169.254, or an RFC1918 range before the actual HTTP request is issued. This time-of-check to time-of-use gap between resolution and connection is the classic DNS rebinding pattern that enables SSRF against otherwise unreachable endpoints.
Because the request originates from the Dynamo process, it inherits the host's network position. Attackers can reach cloud metadata services, orchestrator APIs, or model registries that trust local traffic. The impact profile focuses on confidentiality: response contents or error signals from internal services may be reflected back to the attacker through the fetch pipeline.
Root Cause
The root cause is insufficient enforcement of destination address restrictions during the HTTP connect phase. Validation is performed against the hostname's initial DNS answer rather than against the socket's actual peer address, allowing rebinding to redirect the connection to a disallowed network.
Attack Vector
Exploitation requires the attacker to submit a media URL referencing a hostname under their control with a short TTL. The Dynamo fetcher resolves the hostname, passes validation, then reconnects using a rebound answer that resolves to an internal IP. Response data reachable from the Dynamo host can then be exfiltrated or inferred through the fetcher's return channel. See the NVIDIA security advisory for authoritative technical details.
Detection Methods for CVE-2026-47617
Indicators of Compromise
- Outbound DNS queries from the Dynamo host to attacker-controlled domains with abnormally low TTLs (often under 5 seconds).
- Dynamo media-fetch requests where the resolved address transitions from a public IP to an RFC1918, loopback, or link-local address such as 169.254.169.254.
- Unexpected HTTP requests from the Dynamo service account to cloud metadata endpoints or internal management APIs.
Detection Strategies
- Correlate DNS resolution logs with subsequent TCP connections to identify hostnames that resolve to both external and internal addresses within a short window.
- Alert on any Dynamo-originated traffic destined for 169.254.169.254, loopback interfaces, or internal service subnets.
- Inspect Dynamo application logs for media URLs referencing uncommon TLDs or dynamic DNS providers.
Monitoring Recommendations
- Enable egress logging on the Dynamo host and forward DNS and connection telemetry to a centralized analytics platform.
- Baseline the Dynamo service's normal outbound destinations and alert on deviations.
- Monitor for repeated fetch requests to the same hostname that produce mixed public and private resolution results.
How to Mitigate CVE-2026-47617
Immediate Actions Required
- Apply the fixed release identified in the NVIDIA product security advisory for CVE-2026-47617.
- Restrict inbound access to the Dynamo media-fetch API so only trusted callers can submit URLs.
- Block outbound access from the Dynamo host to cloud metadata endpoints and internal management ranges at the network layer.
Patch Information
NVIDIA has published the advisory under identifier 5842. Consult the vendor page for the specific fixed version and upgrade procedure for your deployment channel.
Workarounds
- Deploy Dynamo behind an egress proxy that re-resolves and enforces destination address policy at connect time, blocking private and link-local ranges.
- Enforce IMDSv2 or equivalent session-based metadata protections on the underlying cloud host to reduce the value of any SSRF pivot.
- Configure the Dynamo host firewall to deny outbound traffic to loopback, RFC1918, and metadata addresses except for explicitly required destinations.
# Example iptables rules blocking SSRF pivot targets from the Dynamo service user
iptables -A OUTPUT -m owner --uid-owner dynamo -d 169.254.169.254 -j REJECT
iptables -A OUTPUT -m owner --uid-owner dynamo -d 127.0.0.0/8 -j REJECT
iptables -A OUTPUT -m owner --uid-owner dynamo -d 10.0.0.0/8 -j REJECT
iptables -A OUTPUT -m owner --uid-owner dynamo -d 172.16.0.0/12 -j REJECT
iptables -A OUTPUT -m owner --uid-owner dynamo -d 192.168.0.0/16 -j REJECT
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
