Security readout for executives and security teams
Plain-English summary
CVE-2021-1421 affects Cisco Enterprise NFV Infrastructure Software. A logged-in local user with restricted CLI access could inject commands through a configuration command and run operating system commands as root. This is not remote unauthenticated exposure, but it can turn low-privileged local access into full device compromise.
Executive priority
Treat as high priority where NFVIS is deployed and local CLI access is broadly assigned. The business risk is privilege escalation to root on network virtualization infrastructure, not internet-scale unauthenticated compromise.
Technical view
The issue is CWE-78 command injection caused by insufficient validation of user-supplied input to a configuration command. The CVSS 3.1 vector is local, low complexity, low privileges, no user interaction, unchanged scope, with high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to organizations running Cisco Enterprise NFV Infrastructure Software where a non-privileged local authenticated user can access the restricted CLI. The source bundle does not provide affected version ranges or CPEs.
Exploitation context
The CVE record describes local authenticated exploitation through malicious input during command execution. The bundle marks KEV as false and provides no cited evidence of active exploitation in the wild.
Researcher notes
Evidence is limited to the CVE metadata and Cisco advisory reference. Do not assume affected versions, exploit availability, or fixed versions beyond vendor guidance. The key validation question is whether low-privileged restricted CLI users exist on NFVIS systems.
Mitigation direction
- Inventory Cisco Enterprise NFV Infrastructure Software deployments.
- Check Cisco's advisory for affected-release and fixed-release guidance.
- Restrict restricted CLI access to trusted administrative users only.
- Review local accounts and remove unnecessary NFVIS access.
- Monitor for unexpected privileged OS activity on affected devices.
Validation and detection
- Confirm whether Cisco Enterprise NFV Infrastructure Software is deployed.
- Compare installed NFVIS releases against Cisco advisory guidance.
- Review who has restricted CLI access on each appliance.
- Check logs for suspicious configuration command usage.
- Assess whether exposed local accounts are still required.
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-78: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-1421 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
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20210505 Cisco Enterprise NFV Infrastructure Software Command Injection 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.