How severe is CVE-2021-21538?

CVE-2021-21538 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability low.

Is CVE-2021-21538 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21538?

CVE-2021-21538 affects Dell Idrac9 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21538?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-21538 published?

CVE-2021-21538 was published on 2021-07-29 and last updated on 2026-06-17.

CVE-2021-21538

CVE-2021-21538 is a critical-severity vulnerability in Dell Idrac9 Firmware with a CVSS 3.x base score of 9.6. 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-287.

Key facts

Severity: Critical (CVSS 3.x base score 9.6)
CVSS v2: 7.5
EPSS exploit prediction: 2% (75th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Dell Idrac9 Firmware
Published: 2021-07-29
Last modified: 2026-06-17

Description

Dell EMC iDRAC9 versions 4.40.00.00 and later, but prior to 4.40.10.00, contain an improper authentication vulnerability. A remote unauthenticated attacker could potentially exploit this vulnerability to gain access to the virtual console.

Frequently asked questions

What is CVE-2021-21538?: Dell EMC iDRAC9 versions 4.40.00.00 and later, but prior to 4.40.10.00, contain an improper authentication vulnerability. A remote unauthenticated attacker could potentially exploit this vulnerability to gain access to the virtual console.
How severe is CVE-2021-21538?: CVE-2021-21538 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability low.
Is CVE-2021-21538 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21538?: CVE-2021-21538 affects Dell Idrac9 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21538?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-21538 published?: CVE-2021-21538 was published on 2021-07-29 and last updated on 2026-06-17.

References

https://www.dell.com/support/kbdoc/000186420

Affected products (1)

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

More vulnerabilities in Dell Idrac9 Firmware

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CVE-2019-3707 — High (CVSS 8.6): Dell EMC iDRAC9 versions prior to 3.30.30.30 contain an authentication bypass vulnerability. A remote attacker may…
CVE-2019-3706 — High (CVSS 8.6): Dell EMC iDRAC9 versions prior to 3.24.24.24, 3.21.26.22, 3.22.22.22 and 3.21.25.22 contain an authentication bypass…
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CVE-2020-5366 — High (CVSS 7.1): Dell EMC iDRAC9 versions prior to 4.20.20.20 contain a Path Traversal Vulnerability. A remote authenticated malicious…

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Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
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CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

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