How severe is CVE-2020-3994?

CVE-2020-3994 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2020-3994 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-3994?

CVE-2020-3994 primarily affects Vmware Cloud Foundation. In total, 30 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-3994?

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-2020-3994 published?

CVE-2020-3994 was published on 2020-10-20 and last updated on 2026-06-17.

CVE-2020-3994

CVE-2020-3994 is a high-severity vulnerability in Vmware Cloud Foundation with a CVSS 3.x base score of 7.4. 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-295.

Key facts

Severity: High (CVSS 3.x base score 7.4)
CVSS v2: 5.8
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-295
Affected product: Vmware Cloud Foundation
Published: 2020-10-20
Last modified: 2026-06-17

Description

VMware vCenter Server (6.7 before 6.7u3, 6.6 before 6.5u3k) contains a session hijack vulnerability in the vCenter Server Appliance Management Interface update function due to a lack of certificate validation. A malicious actor with network positioning between vCenter Server and an update repository may be able to perform a session hijack when the vCenter Server Appliance Management Interface is used to download vCenter updates.

Frequently asked questions

What is CVE-2020-3994?: VMware vCenter Server (6.7 before 6.7u3, 6.6 before 6.5u3k) contains a session hijack vulnerability in the vCenter Server Appliance Management Interface update function due to a lack of certificate validation. A malicious actor with network positioning between vCenter Server and an update repository may be able to perform a session hijack when the vCenter Server Appliance Management Interface is used to download vCenter updates.
How severe is CVE-2020-3994?: CVE-2020-3994 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2020-3994 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-3994?: CVE-2020-3994 primarily affects Vmware Cloud Foundation. In total, 30 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-3994?: 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-2020-3994 published?: CVE-2020-3994 was published on 2020-10-20 and last updated on 2026-06-17.

References

https://www.vmware.com/security/advisories/VMSA-2020-0023.html

Affected products (30)

cpe:2.3:a:vmware:cloud_foundation:*:*:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:-:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:a:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:b:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:c:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:d:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:e:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:f:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update1:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update1b:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update1c:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update1d:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update1e:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update1g:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update2:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update2b:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update2c:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update2d:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update2g:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update3:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.5:update3d:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.7:-:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.7:a:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.7:b:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.7:d:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.7:update1:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.7:update1b:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.7:update2:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.7:update2a:*:*:*:*:*:*
cpe:2.3:a:vmware:vcenter_server:6.7:update2c:*:*:*:*:*:*

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