CVE-2025-20348 Overview
CVE-2025-20348 is a missing authorization vulnerability in the REST API endpoints of Cisco Nexus Dashboard and Cisco Nexus Dashboard Fabric Controller (NDFC). The flaw allows an authenticated, low-privileged, remote attacker to view sensitive configuration data and upload or modify files on affected devices. Successful exploitation enables limited administrator functions, including access to HTTP proxy and Network Time Protocol (NTP) configuration data, image uploads, and image file tampering. The weakness is classified under [CWE-201: Insertion of Sensitive Information Into Sent Data].
Critical Impact
A low-privileged authenticated user can retrieve sensitive infrastructure configuration and corrupt image files used by Nexus Dashboard, undermining the integrity of managed fabric devices.
Affected Products
- Cisco Nexus Dashboard
- Cisco Nexus Dashboard Fabric Controller (NDFC)
- Deployments exposing REST API endpoints to authenticated users
Discovery Timeline
- 2025-08-27 - CVE-2025-20348 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-20348
Vulnerability Analysis
The vulnerability exists in a subset of REST API endpoints exposed by Cisco Nexus Dashboard and NDFC. These endpoints perform authentication but fail to enforce role-based authorization checks. As a result, a user holding low-privilege credentials can invoke functions restricted to administrators. The scope is marked as changed because the vulnerable component impacts resources beyond its own security boundary, specifically managed fabric image files and configuration data.
Exploitation does not require user interaction and can be performed remotely over the network. The confidentiality impact is limited to specific configuration data rather than full system disclosure. The integrity impact stems from the ability to upload and damage image files staged on the appliance.
Root Cause
The root cause is missing authorization controls on certain REST API handlers. Authentication is validated, but the endpoints do not verify that the calling user holds the administrator role required to read HTTP proxy settings, read NTP settings, or write image files. This is a broken access control pattern that separates authentication from authorization enforcement.
Attack Vector
An attacker with valid low-privileged credentials sends crafted HTTP requests to the affected REST API endpoints on the Nexus Dashboard management interface. The requests reach handler code that returns sensitive configuration values or accepts file upload payloads without validating the caller's role. The attacker can then retrieve proxy and NTP configuration, upload rogue images, or corrupt legitimate image files.
No verified public exploit code is available for CVE-2025-20348. See the Cisco Security Advisory for vendor technical details.
Detection Methods for CVE-2025-20348
Indicators of Compromise
- Unexpected REST API calls to Nexus Dashboard or NDFC endpoints from low-privileged user accounts targeting proxy, NTP, or image management resources.
- Image files on the appliance with modified timestamps, altered hashes, or unexpected filenames that do not correspond to administrator activity.
- API audit log entries showing successful read or upload operations by users lacking administrator role assignment.
Detection Strategies
- Enable and centralize Nexus Dashboard API audit logging, then alert on privileged operations performed by non-administrator principals.
- Baseline expected API callers per endpoint and flag deviations, especially unusual sources issuing image upload requests.
- Correlate authentication events with subsequent API activity to identify accounts issuing administrator-scoped requests shortly after login.
Monitoring Recommendations
- Forward Nexus Dashboard and NDFC audit logs to a centralized security analytics platform for retention and correlation.
- Monitor file integrity on staged image directories to detect unauthorized modification or replacement.
- Track failed and successful authorization decisions on management APIs and alert on anomalous patterns from service accounts.
How to Mitigate CVE-2025-20348
Immediate Actions Required
- Apply the fixed software release identified in the Cisco Security Advisory cisco-sa-nshs-urapi-gJuBVFpu for Nexus Dashboard and NDFC.
- Review all Nexus Dashboard user accounts and remove or reduce low-privileged accounts that no longer require access.
- Rotate credentials for any user or service account that had access to affected clusters during the exposure window.
- Audit HTTP proxy and NTP configurations for signs of unauthorized access or tampering.
Patch Information
Cisco has published fixed software versions in security advisory cisco-sa-nshs-urapi-gJuBVFpu. Refer to the advisory's Fixed Software section for the specific Nexus Dashboard and NDFC release trains that contain the authorization enforcement fix, and plan an upgrade following Cisco's documented upgrade procedures.
Workarounds
- No vendor-documented workarounds are listed in the advisory; upgrading to a fixed release is the required remediation.
- Restrict network access to the Nexus Dashboard management interface using access control lists so that only trusted administrative hosts can reach REST API endpoints.
- Enforce the principle of least privilege for all Nexus Dashboard accounts and remove unused local users pending patch deployment.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
