Security readout for executives and security teams
Plain-English summary
CVE-2021-1406 can let a highly privileged authenticated user download files that improperly contain sensitive data from Cisco Unified CM or Unified CM SME. The key business risk is exposure of hashed system-user credentials, which could support later credential misuse if an attacker already has elevated access.
Executive priority
Treat this as a targeted credential-exposure risk, not an unauthenticated internet-wide emergency. Prioritize organizations where Unified CM is critical, admin access is broad, or credential compromise is already suspected.
Technical view
The flaw is an information disclosure issue caused by sensitive information being included in downloadable files. It is network-reachable, requires high privileges, needs no user interaction, and affects confidentiality only. Cisco’s description says successful exploitation may expose hashed credentials of system users. Affected version detail is not provided in the source bundle.
Likely exposure
Exposure is most likely in organizations running Cisco Unified Communications Manager or Unified CM Session Management Edition where elevated administrative credentials exist or could be misused. The provided sources do not list specific vulnerable versions in the bundle, so version validation must be done against Cisco’s advisory.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. Exploitation requires valid elevated credentials on the affected system, which limits broad opportunistic risk but increases concern after administrator account compromise.
Researcher notes
Mapped to CWE-538. CVSS is 4.9 with AV:N, AC:L, PR:H, UI:N, S:U, C:H, I:N, A:N. The main uncertainty is affected-version and fixed-release detail, which is only referenced through Cisco’s advisory, not enumerated in the bundle.
Mitigation direction
- Review Cisco’s advisory and apply any fixed release or workaround it identifies.
- Restrict elevated Unified CM and Unified CM SME accounts to administrators with a current business need.
- Audit elevated accounts and remove unused, shared, or stale credentials.
- If exposure is suspected, rotate affected system-user credentials and investigate credential reuse.
- Monitor for unusual authenticated administrative download activity on affected systems.
Validation and detection
- Inventory Cisco Unified CM and Unified CM SME deployments.
- Compare deployed versions and configurations with Cisco’s advisory.
- Review administrative account membership for excessive or stale elevated access.
- Check audit logs for unexpected elevated authenticated access or file downloads.
- Confirm whether any exposed hashed credentials require rotation.
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-538: 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-2021-1406 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
- 4.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/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:H/UI:N/S:U/C:H/I:N/A:N1.23.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.9MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20210407 Cisco Unified Communications Manager Information Disclosure 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.
Insertion of Sensitive Information into Externally-Accessible File or Directory
Insertion of Sensitive Information into Externally-Accessible File or Directory represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.