How severe is CVE-2020-3977?

CVE-2020-3977 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2020-3977 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-3977?

CVE-2020-3977 primarily affects Vmware Horizon Daas. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-3977?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-3977 published?

CVE-2020-3977 was published on 2020-09-22 and last updated on 2026-06-17.

CVE-2020-3977

CVE-2020-3977 is a medium-severity vulnerability in Vmware Horizon Daas with a CVSS 3.x base score of 6.5. 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-306.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Affected product: Vmware Horizon Daas
Published: 2020-09-22
Last modified: 2026-06-17

Description

VMware Horizon DaaS (7.x and 8.x before 8.0.1 Update 1) contains a broken authentication vulnerability due to a flaw in the way it handled the first factor authentication. Successful exploitation of this issue may allow an attacker to bypass two-factor authentication process. In order to exploit this issue, an attacker must have a legitimate account on Horizon DaaS.

Frequently asked questions

What is CVE-2020-3977?: VMware Horizon DaaS (7.x and 8.x before 8.0.1 Update 1) contains a broken authentication vulnerability due to a flaw in the way it handled the first factor authentication. Successful exploitation of this issue may allow an attacker to bypass two-factor authentication process. In order to exploit this issue, an attacker must have a legitimate account on Horizon DaaS.
How severe is CVE-2020-3977?: CVE-2020-3977 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2020-3977 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-3977?: CVE-2020-3977 primarily affects Vmware Horizon Daas. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-3977?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-3977 published?: CVE-2020-3977 was published on 2020-09-22 and last updated on 2026-06-17.

References

https://www.vmware.com/security/advisories/VMSA-2020-0021.html

Affected products (2)

cpe:2.3:a:vmware:horizon_daas:*:*:*:*:*:*:*:*
cpe:2.3:a:vmware:horizon_daas:7.0.0:*:*:*:*:*:*:*

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