Security readout for executives and security teams
Plain-English summary
This is a Dell EMC iDRAC9 firmware flaw that could let a logged-in remote attacker corrupt configuration information by sending oversized input. It does not expose data according to the CVSS vector, but it can affect integrity and some availability. The supplied sources identify iDRAC9 versions before 4.40.00.00 as affected.
Executive priority
Prioritize remediation during the next infrastructure maintenance window, sooner for internet-exposed or broadly reachable management networks. The issue is not described as actively exploited, but iDRAC controls server management and configuration, making integrity risk operationally meaningful.
Technical view
CVE-2021-21540 is a stack-based overflow in Dell EMC iDRAC9 before 4.40.00.00. The CVSS 3.1 vector is AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L. Exploitation requires network access, low privileges, no user interaction, and high attack complexity, with primary impact to configuration integrity.
Likely exposure
Exposure is most relevant where Dell EMC iDRAC9 management interfaces are reachable by authenticated users or management networks. Systems running versions prior to 4.40.00.00 should be treated as potentially affected.
Exploitation context
The supplied bundle does not show CISA KEV listing or active exploitation evidence. The attacker must already authenticate, and exploitation is rated high complexity, reducing broad opportunistic risk while preserving concern for insider, compromised-account, or poorly segmented management environments.
Researcher notes
Evidence is limited to the CVE description, CVSS vector, affected version boundary, CWE-121 classification, and Dell advisory reference. The supplied sources do not provide exploit details, workaround specifics, or proof of active exploitation.
Mitigation direction
- Update affected Dell EMC iDRAC9 firmware to 4.40.00.00 or later.
- Confirm the exact upgrade path against Dell advisory 000185293.
- Restrict iDRAC access to trusted management networks only.
- Review iDRAC accounts and remove unnecessary low-privilege access.
- Monitor for unexpected iDRAC configuration changes.
Validation and detection
- Inventory Dell EMC iDRAC9 firmware versions across managed servers.
- Flag any iDRAC9 version below 4.40.00.00.
- Verify iDRAC interfaces are not reachable from untrusted networks.
- Review logs for unusual authenticated configuration activity.
- Confirm post-update firmware version and configuration integrity.
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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CWE-121: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-21540 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
- 5.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/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:N/S:U/C:N/I:H/A:L1.64.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.9MediumVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/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.
Stack-based Buffer Overflow
Stack-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.