Security readout for executives and security teams
Plain-English summary
CVE-2021-1370 lets a logged-in user on certain Cisco carrier-grade routers potentially become root. This is not a remote unauthenticated issue, but it matters because root access can expose routing infrastructure to full compromise, configuration tampering, or service disruption.
Executive priority
Treat this as a high-priority network infrastructure risk where affected routers have multiple administrators, third-party access, or weak account hygiene. The issue is less urgent than unauthenticated internet exploitation, but root compromise on routing equipment can have severe operational impact.
Technical view
Cisco describes insufficient validation of command-line arguments in a Cisco IOS XR CLI command. An authenticated local attacker with a valid account could enter a crafted command and escalate from low privileges to root. The CVSS v3.0 score is 7.8, with high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to Cisco IOS XR Software on Cisco 8000 Series Routers and Cisco Network Convergence System 540 Series Routers running NCS540L software images, where untrusted or low-privilege users can access the device CLI.
Exploitation context
The provided sources do not indicate active exploitation, and this CVE is not marked KEV. Exploitation requires valid local authentication and CLI access, so the main risk is misuse of compromised, shared, stale, or overly broad router accounts.
Researcher notes
The key exposure condition is authenticated local CLI access. The weakness is mapped to CWE-78 and stems from insufficient command-line argument validation. The source bundle does not include exploit proof, active exploitation evidence, or specific fixed versions.
Mitigation direction
- Review Cisco's advisory for affected releases, fixed software, and vendor workarounds.
- Restrict CLI access to trusted administrators only.
- Remove unnecessary local accounts and stale credentials.
- Prepare maintenance windows if Cisco guidance identifies an applicable fixed release.
- Monitor privileged activity on affected router management planes.
Validation and detection
- Inventory Cisco IOS XR 8000 and NCS 540 devices.
- Identify systems running NCS540L software images.
- Compare installed software against Cisco's CVE-2021-1370 advisory.
- Review low-privilege accounts with CLI access.
- Check logs for unexpected privilege changes or root-level activity.
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 lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-1370 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 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/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:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
7.8HighVector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20210203 Cisco IOS XR Software for Cisco 8000 Series Routers and Network Convergence System 540 Series Routers Privilege Escalation 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.
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.