How severe is CVE-2021-21539?

CVE-2021-21539 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity high, and availability low.

Is CVE-2021-21539 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21539?

CVE-2021-21539 affects Dell Idrac9 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21539?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-21539 published?

CVE-2021-21539 was published on 2021-04-30 and last updated on 2026-06-17.

CVE-2021-21539

CVE-2021-21539 is a medium-severity vulnerability in Dell Idrac9 Firmware with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-367.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 4.6
EPSS exploit prediction: 1% (45th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-367
Affected product: Dell Idrac9 Firmware
Published: 2021-04-30
Last modified: 2026-06-17

Description

Dell EMC iDRAC9 versions prior to 4.40.00.00 contain a Time-of-check Time-of-use (TOCTOU) race condition vulnerability. A remote authenticated attacker could potentially exploit this vulnerability to gain elevated privileges when a user with higher privileges is simultaneously accessing iDRAC through the web interface.

Frequently asked questions

What is CVE-2021-21539?: Dell EMC iDRAC9 versions prior to 4.40.00.00 contain a Time-of-check Time-of-use (TOCTOU) race condition vulnerability. A remote authenticated attacker could potentially exploit this vulnerability to gain elevated privileges when a user with higher privileges is simultaneously accessing iDRAC through the web interface.
How severe is CVE-2021-21539?: CVE-2021-21539 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity high, and availability low.
Is CVE-2021-21539 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21539?: CVE-2021-21539 affects Dell Idrac9 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21539?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-21539 published?: CVE-2021-21539 was published on 2021-04-30 and last updated on 2026-06-17.

References

https://www.dell.com/support/kbdoc/000185293

Affected products (1)

cpe:2.3:o:dell:idrac9_firmware:*:*:*:*:*:*:*:*

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