Security readout for executives and security teams
Plain-English summary
This Cisco NX-OS flaw could let an unauthenticated remote attacker change critical files on affected Nexus switches. The business risk is loss of control over network infrastructure, including hidden account creation or configuration tampering. The bundle does not show confirmed active exploitation.
Executive priority
Treat as urgent for exposed Nexus infrastructure. Prioritize internet-facing or broadly reachable management networks first, then complete vendor-guided upgrades and exposure reduction across the fleet.
Technical view
CVE-2021-1361 affects Cisco Nexus 3000 and Nexus 9000 switches in standalone NX-OS mode. An internal file management service incorrectly listens externally on TCP port 9075, allowing crafted TCP traffic to create, delete, or overwrite arbitrary files with root privileges.
Likely exposure
Exposure is likely where affected Nexus 3000 or 9000 standalone NX-OS switches have reachable local interface IPs and TCP port 9075 accessible from attacker-controlled networks. Exact affected versions are not provided in the bundle.
Exploitation context
The CVSS score is 9.8 because exploitation is remote, unauthenticated, low complexity, and requires no user interaction. KEV is false, and the provided sources do not establish active exploitation.
Researcher notes
The issue is CWE-552 exposure of an internal file management service. The source bundle names root-privileged arbitrary file actions but does not include fixed versions, workarounds, exploit evidence, or detection indicators.
Mitigation direction
- Check Cisco’s advisory for affected and fixed NX-OS releases.
- Upgrade affected standalone NX-OS switches according to Cisco guidance.
- Restrict TCP 9075 exposure to trusted management networks only.
- Review switch configuration and user accounts for unauthorized changes.
- Increase monitoring for unexpected configuration or file changes.
Validation and detection
- Inventory Nexus 3000 and 9000 switches running standalone NX-OS.
- Compare installed NX-OS releases against Cisco’s advisory.
- Confirm whether TCP 9075 is reachable on local interface IPs.
- Review administrative users for unexpected additions or privilege changes.
- Check recent configuration changes for unexplained file or account modifications.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-552: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-1361 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20210224 Cisco NX-OS Software Unauthenticated Arbitrary File Actions VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Files or Directories Accessible to External Parties
Files or Directories Accessible to External Parties represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.