Security readout for executives and security teams
Plain-English summary
CVE-2021-1540 affects Cisco ASR 5000 Series Software. An authenticated remote user could bypass authorization and run some CLI commands they should not be allowed to run. For organizations operating these carrier-grade devices, this is high urgency because the CVSS vector indicates potential major confidentiality and availability impact.
Executive priority
Treat this as high priority where ASR 5000 devices are in service, especially in production network infrastructure. The practical risk depends on whether low-privileged authenticated users can reach device management interfaces.
Technical view
Cisco describes multiple authorization-process vulnerabilities in ASR 5000 Series Software, also known as StarOS. The issue is CWE-863 and requires low privileges, network access, and no user interaction. The provided CVSS 3.1 score is 8.1, with high confidentiality and availability impact but no integrity impact in the vector.
Likely exposure
Exposure is likely limited to organizations running Cisco ASR 5000 Series Software. The bundle does not provide affected version ranges or CPEs, so vulnerability managers must validate exposure against Cisco’s advisory and internal asset records.
Exploitation context
The source bundle does not show CISA KEV listing or other evidence of active exploitation. Exploitation requires an authenticated remote attacker with low privileges. No public exploit details are provided in the supplied sources.
Researcher notes
The evidence supports authorization bypass after authentication, not unauthenticated takeover. The source bundle lacks affected versions, fixed releases, and detailed command scope, so conclusions should stay bounded to Cisco’s public description and CVSS vector.
Mitigation direction
- Identify all Cisco ASR 5000 Series Software or StarOS deployments.
- Consult Cisco’s advisory for affected-release and remediation guidance.
- Prioritize remediation for devices reachable through administrative or management networks.
- Restrict management-plane access to authorized administrative paths where possible.
- Review least-privilege controls for CLI-capable accounts.
Validation and detection
- Check inventory for Cisco ASR 5000 Series Software or StarOS assets.
- Compare installed releases against Cisco’s advisory; this bundle lacks version ranges.
- Review user roles with CLI access on potentially affected devices.
- Inspect administrative logs for unexpected CLI activity by authenticated users.
- Confirm remediation status is tracked for each affected device.
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-863: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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-2021-1540 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
- 8.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/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:L/UI:N/S:U/C:H/I:N/A:H2.85.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20210602 Cisco ASR 5000 Series Software Authorization Bypass VulnerabilitiesCVE 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.
Incorrect Authorization
Incorrect Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.