Security readout for executives and security teams
Plain-English summary
CVE-2021-1135 affects Cisco Data Center Network Manager. An authenticated remote user may be able to access REST API functions beyond their authorization, including viewing, changing, or deleting data. The business risk is unauthorized changes in a network management platform, but the provided CVSS rating is medium and requires credentials.
Executive priority
Treat this as a targeted remediation item for environments using Cisco DCNM. Prioritize validation because network management tools can affect operational integrity, but urgency is moderated by credential requirements, medium CVSS score, and no cited active exploitation.
Technical view
The issue is in Cisco DCNM REST API authorization handling. The CVSS 3.1 vector is AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N, score 4.6. The CWE is CWE-184. The source bundle does not specify affected versions, fixed releases, or detailed per-endpoint behavior.
Likely exposure
Exposure is most likely where Cisco Data Center Network Manager is deployed and its REST API is reachable by authenticated users. The bundle lists affected versions as n/a, so asset owners must confirm applicability against Cisco’s advisory and local inventory.
Exploitation context
The source bundle and KEV flag do not show known active exploitation. The vulnerability requires an authenticated remote attacker and user interaction per the CVSS vector. No exploit details or public weaponization evidence are provided in the bundle.
Researcher notes
Evidence is limited to the CVE record and Cisco advisory reference in the bundle. The affected version range and remediation details are not included here. Avoid assuming endpoint scope, exploitability beyond CVSS, or patch availability without consulting the Cisco advisory directly.
Mitigation direction
- Review Cisco’s advisory for affected releases, fixed releases, and official workarounds.
- Inventory Cisco DCNM deployments and identify reachable REST API surfaces.
- Restrict DCNM management access to trusted administrative networks where feasible.
- Review DCNM user roles and remove unnecessary low-privilege access.
- Monitor DCNM REST API activity for unauthorized data changes or deletions.
Validation and detection
- Confirm whether Cisco DCNM is present in the environment.
- Compare installed DCNM versions against Cisco advisory guidance.
- Verify REST API access is limited to intended administrative users.
- Review role assignments for least-privilege alignment.
- Check logs for unexpected REST API reads, updates, or deletions.
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-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-2021-1135 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.