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.

Published: 2020-09-22 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-3977 is rated Moderate Risk (45.9/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.96%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-3977

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-17 0.95% 0.96% +0.01%
2 2026-06-15 0.05% 0.95% +0.89%
3 2023-03-07 — 0.05% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-3977

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 3.6 [email protected]
4.0 2.0 MEDIUM
AV:N/AC:L/Au:S/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.0 2.9 [email protected]

Weakness enumeration for CVE-2020-3977

Affected software / configurations for CVE-2020-3977

Vendor Product Version Raw CPE
vmware horizon_daas >= 8.0.0, <= 8.0.1 cpe:2.3:a:vmware:horizon_daas:*:*:*:*:*:*:*:*
vmware horizon_daas 7.0.0 cpe:2.3:a:vmware:horizon_daas:7.0.0:*:*:*:*:*:*:*

References for CVE-2020-3977

cvelogic Threat Intelligence