Security readout for executives and security teams
Plain-English summary
CVE-2021-1255 affects Cisco Data Center Network Manager. A logged-in remote attacker with low privileges may be able to view, modify, or delete data they should not be authorized to access through the REST API. The CVSS score is medium, and no CISA KEV listing is provided.
Executive priority
Treat this as a moderate-priority network management platform risk. It is not reported as actively exploited in the provided sources, but unauthorized changes inside DCNM could affect operational trust in data center network management. Prioritize confirmation of exposure and vendor-supported remediation.
Technical view
The issue is an authorization weakness in Cisco DCNM REST API endpoints, mapped to CWE-184. The CVSS v3.1 vector is AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N, indicating network reachability, low attack complexity, required low privileges and user interaction, with limited confidentiality and integrity impact.
Likely exposure
Exposure is likely limited to organizations running Cisco Data Center Network Manager with REST API access available to authenticated users. The source bundle does not identify specific affected versions, deployment modes, or internet exposure assumptions, so asset inventory and Cisco advisory review are necessary.
Exploitation context
The bundle does not cite active exploitation, public exploit use, or KEV inclusion. The vulnerability requires authentication and user interaction according to the CVSS vector, which lowers urgency compared with unauthenticated remote bugs but still matters for insider, compromised-account, or over-privileged-user scenarios.
Researcher notes
The public bundle is sparse: affected versions are listed as n/a and no fix details are included outside the Cisco advisory reference. Analysis should stay tied to Cisco's advisory, the CVSS vector, and authenticated authorization impact. Do not assume broader Cisco products are affected.
Mitigation direction
- Review Cisco's advisory for affected releases, fixed versions, and official workarounds.
- Inventory all Cisco DCNM instances and confirm whether REST API access is enabled.
- Limit DCNM REST API access to trusted administrative networks where feasible.
- Review DCNM user roles and remove unnecessary low-privilege accounts.
- Monitor DCNM audit logs for unexpected data reads, changes, or deletions.
Validation and detection
- Compare deployed Cisco DCNM versions against Cisco's advisory once version details are confirmed.
- Confirm which users or service accounts can authenticate to DCNM REST API endpoints.
- Review authorization controls for low-privileged users without testing offensive payloads.
- Check logs for unusual authenticated API activity around sensitive objects.
- Document any exposed management interfaces and compensating network controls.
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-184: 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 lookupCVE-2021-1255 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
- Medium
- CVSS
- 4.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
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:R/S:U/C:L/I:L/A:N2.12.5Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.6MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20210120 Cisco Data Center Network Manager REST API 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.
Incomplete List of Disallowed Inputs
Incomplete List of Disallowed Inputs represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.