Security readout for executives and security teams
Plain-English summary
This affects Dell EMC iDRAC9 management controllers before version 4.40.00.00. A logged-in low-privilege attacker may be able to gain higher privileges, but only during a narrow race condition while a more privileged user is using the iDRAC web interface.
Executive priority
Treat this as a moderate infrastructure management-plane issue. It is not described as actively exploited, but iDRAC compromise can affect server control and operational integrity. Prioritize firmware remediation during normal vulnerability cycles.
Technical view
CVE-2021-21539 is a TOCTOU race condition in Dell EMC iDRAC9 prior to 4.40.00.00. The CVSS 3.1 vector is network-accessible, high complexity, low privileges required, and user interaction required. Potential impact includes low confidentiality loss, high integrity impact, and low availability impact.
Likely exposure
Organizations are exposed if they run Dell EMC iDRAC9 below 4.40.00.00 and allow authenticated low-privilege access to the iDRAC web interface.
Exploitation context
The supplied sources do not show active exploitation. KEV status is false. Exploitation is constrained by authentication, high complexity, and the need for a higher-privileged user to be simultaneously active in the web interface.
Researcher notes
The key condition is concurrent privileged web-interface activity, consistent with a TOCTOU race. The source bundle does not provide exploit details, proof-of-concept status, or Dell mitigation specifics beyond the affected version boundary.
Mitigation direction
- Update affected iDRAC9 firmware to 4.40.00.00 or later.
- Review Dell advisory 000185293 for vendor-specific remediation guidance.
- Limit iDRAC access to trusted management networks.
- Remove unnecessary low-privilege iDRAC accounts.
- Monitor iDRAC administrative activity for unexpected privilege changes.
Validation and detection
- Inventory Dell EMC iDRAC9 devices and firmware versions.
- Confirm no iDRAC9 instance remains below 4.40.00.00.
- Review iDRAC user roles for excessive or stale accounts.
- Check management interface exposure and network access controls.
- Review logs for suspicious privilege or configuration changes.
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
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CVE-2021-21539 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:H/A:L
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:H/PR:L/UI:R/S:U/C:L/I:H/A:L1.24.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.9MediumVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:H/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://www.dell.com/support/kbdoc/000185293CVE reference · x_refsource_MISC
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.