Is CVE-2021-21991 in the CISA KEV catalog?

No. CVE-2021-21991 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-21991?

CVE-2021-21991 has a CVSS v3 base score of 7.8 (HIGH).

What is the EPSS score for CVE-2021-21991?

CVE-2021-21991 has an EPSS score of 0.31% (22th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-21991?

Upgrade cloud foundation to 4.3 or later.

CVE & CISA-KEV Catalog

CVE-2021-21991

HIGH

7.8

CVSS v3

NVD

Description

The vCenter Server contains a local privilege escalation vulnerability due to the way it handles session tokens. A malicious actor with non-administrative user access on vCenter Server host may exploit this issue to escalate privileges to Administrator on the vSphere Client (HTML5) or vCenter Server vSphere Web Client (FLEX/Flash).

How to fix

Remediation Available

cloud foundationNVD

Affected:>= 4.0, < 4.3Fixed in:4.3CVE-2021-21991derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.31%probability of exploitation in 30 days

22ndpercentile

Low risk: more likely to be exploited than 22% of all known CVEs.

References

Patch1

vmware.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.