How severe is CVE-2021-21999?

CVE-2021-21999 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-21999 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21999?

CVE-2021-21999 primarily affects Vmware App Volumes. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-21999?

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-2021-21999 published?

CVE-2021-21999 was published on 2021-06-23 and last updated on 2026-06-17.

CVE-2021-21999

CVE-2021-21999 is a high-severity vulnerability in Vmware App Volumes with a CVSS 3.x base score of 7.8. 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-427.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 7.2
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-427
Affected product: Vmware App Volumes
Published: 2021-06-23
Last modified: 2026-06-17

Description

VMware Tools for Windows (11.x.y prior to 11.2.6), VMware Remote Console for Windows (12.x prior to 12.0.1) , VMware App Volumes (2.x prior to 2.18.10 and 4 prior to 2103) contain a local privilege escalation vulnerability. An attacker with normal access to a virtual machine may exploit this issue by placing a malicious file renamed as `openssl.cnf' in an unrestricted directory which would allow code to be executed with elevated privileges.

Frequently asked questions

What is CVE-2021-21999?: VMware Tools for Windows (11.x.y prior to 11.2.6), VMware Remote Console for Windows (12.x prior to 12.0.1) , VMware App Volumes (2.x prior to 2.18.10 and 4 prior to 2103) contain a local privilege escalation vulnerability. An attacker with normal access to a virtual machine may exploit this issue by placing a malicious file renamed as `openssl.cnf' in an unrestricted directory which would allow code to be executed with elevated privileges.
How severe is CVE-2021-21999?: CVE-2021-21999 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-21999 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21999?: CVE-2021-21999 primarily affects Vmware App Volumes. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-21999?: 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-2021-21999 published?: CVE-2021-21999 was published on 2021-06-23 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:vmware:app_volumes:*:*:*:*:*:*:*:*
cpe:2.3:a:vmware:remote_console:*:*:*:*:*:windows:*:*
cpe:2.3:a:vmware:tools:*:*:*:*:*:windows:*:*

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