How severe is CVE-2021-21511?

CVE-2021-21511 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-21511 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21511?

CVE-2021-21511 primarily affects Dell Emc Avamar Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-21511?

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

When was CVE-2021-21511 published?

CVE-2021-21511 was published on 2021-02-15 and last updated on 2026-06-17.

CVE-2021-21511

CVE-2021-21511 is a high-severity vulnerability in Dell Emc Avamar Server with a CVSS 3.x base score of 8.1. 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-285.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v2: 5.5
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-285
Affected product: Dell Emc Avamar Server
Published: 2021-02-15
Last modified: 2026-06-17

Description

Dell EMC Avamar Server, versions 19.3 and 19.4 contain an Improper Authorization vulnerability in the web UI. A remote low privileged attacker could potentially exploit this vulnerability, to gain unauthorized read or modification access to other users' backup data.

Frequently asked questions

What is CVE-2021-21511?: Dell EMC Avamar Server, versions 19.3 and 19.4 contain an Improper Authorization vulnerability in the web UI. A remote low privileged attacker could potentially exploit this vulnerability, to gain unauthorized read or modification access to other users' backup data.
How severe is CVE-2021-21511?: CVE-2021-21511 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-21511 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21511?: CVE-2021-21511 primarily affects Dell Emc Avamar Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-21511?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-21511 published?: CVE-2021-21511 was published on 2021-02-15 and last updated on 2026-06-17.

References

https://www.dell.com/support/kbdoc/en-us/000182926/dsa-2021-033-dell-emc-avamar-server-improper-authorization-vulnerability

Affected products (3)

cpe:2.3:a:dell:emc_avamar_server:19.3:*:*:*:*:*:*:*
cpe:2.3:a:dell:emc_avamar_server:19.4:*:*:*:*:*:*:*
cpe:2.3:a:dell:emc_integrated_data_protection_appliance:2.6:*:*:*:*:*:*:*

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Other CWE-285 (Improper Authorization) vulnerabilities

CVE-2025-65041 — Critical (CVSS 10.0): Improper authorization in Microsoft Partner Center allows an unauthorized attacker to elevate privileges over a network.
CVE-2023-33189 — Critical (CVSS 10.0): Pomerium is an identity and context-aware access proxy. With specially crafted requests, incorrect authorization…
CVE-2022-2595 — Critical (CVSS 10.0): Improper Authorization in GitHub repository kromitgmbh/titra prior to 0.79.1.
CVE-2021-28799 — Critical (CVSS 10.0): An improper authorization vulnerability has been reported to affect QNAP NAS running HBS 3 (Hybrid Backup Sync. ) If…
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CVE-2026-5412 — Critical (CVSS 9.9): In Juju versions prior to 2.9.57 and 3.6.21, an authorization issue exists in the Controller facade. An authenticated…

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