How severe is CVE-2020-3955?

CVE-2020-3955 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2020-3955 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-3955?

CVE-2020-3955 primarily affects Vmware Esxi. In total, 179 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-3955?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-3955 published?

CVE-2020-3955 was published on 2020-04-29 and last updated on 2026-06-17.

CVE-2020-3955

CVE-2020-3955 is a critical-severity vulnerability in Vmware Esxi with a CVSS 3.x base score of 9.3. 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-79.

Key facts

Severity: Critical (CVSS 3.x base score 9.3)
CVSS v2: 4.3
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Vmware Esxi
Published: 2020-04-29
Last modified: 2026-06-17

Description

ESXi 6.5 without patch ESXi650-201912104-SG and ESXi 6.7 without patch ESXi670-202004103-SG do not properly neutralize script-related HTML when viewing virtual machines attributes. VMware has evaluated the severity of this issue to be in the Important severity range with a maximum CVSSv3 base score of 8.3.

Frequently asked questions

What is CVE-2020-3955?: ESXi 6.5 without patch ESXi650-201912104-SG and ESXi 6.7 without patch ESXi670-202004103-SG do not properly neutralize script-related HTML when viewing virtual machines attributes. VMware has evaluated the severity of this issue to be in the Important severity range with a maximum CVSSv3 base score of 8.3.
How severe is CVE-2020-3955?: CVE-2020-3955 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2020-3955 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-3955?: CVE-2020-3955 primarily affects Vmware Esxi. In total, 179 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-3955?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-3955 published?: CVE-2020-3955 was published on 2020-04-29 and last updated on 2026-06-17.

References

https://www.vmware.com/security/advisories/VMSA-2020-0008.html

Affected products (179)

cpe:2.3:o:vmware:esxi:6.5:-:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:2:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201701001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201703001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201703002:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201704001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707101:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707102:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707103:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707201:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707202:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707203:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707204:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707205:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707206:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707207:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707208:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707209:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707210:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707211:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707212:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707213:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707214:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707215:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707216:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707217:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707218:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707219:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707220:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201707221:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201710001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201712001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201803001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201806001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201808001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201810001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201810002:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201811001:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201811002:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.5:650-201811301:*:*:*:*:*:*

More vulnerabilities in Vmware Esxi

CVE-2013-1405 — Critical (CVSS 10.0): VMware vCenter Server 4.0 before Update 4b and 4.1 before Update 3a, VMware VirtualCenter 2.5, VMware vSphere Client…
CVE-2012-1516 — Critical (CVSS 9.9): The VMX process in VMware ESXi 3.5 through 4.1 and ESX 3.5 through 4.1 does not properly handle RPC commands, which…
CVE-2021-21994 — Critical (CVSS 9.8): SFCB (Small Footprint CIM Broker) as used in ESXi has an authentication bypass vulnerability. A malicious actor with…
CVE-2020-3992 — Critical (CVSS 9.8): OpenSLP as used in VMware ESXi (7.0 before ESXi_7.0.1-0.0.16850804, 6.7 before ESXi670-202010401-SG, 6.5 before…
CVE-2019-5544 — Critical (CVSS 9.8): OpenSLP as used in ESXi and the Horizon DaaS appliances has a heap overwrite issue. VMware has evaluated the severity…
CVE-2010-0211 — Critical (CVSS 9.8): The slap_modrdn2mods function in modrdn.c in OpenLDAP 2.4.22 does not check the return value of a call to the…

All CVEs affecting Vmware Esxi →

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

CVE-2025-49410 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Imran Emu TC…
CVE-2024-47875 — Critical (CVSS 10.0): DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. DOMpurify was vulnerable to…
CVE-2024-6886 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Gitea…
CVE-2023-45144 — Critical (CVSS 10.0): com.xwiki.identity-oauth:identity-oauth-ui is a package to aid in building identity and service providers based on…
CVE-2023-45138 — Critical (CVSS 10.0): Change Request is an pplication allowing users to request changes on a wiki without publishing the changes directly.…
CVE-2022-4361 — Critical (CVSS 10.0): Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the…

Browse all CWE-79 (Cross-site Scripting (XSS)) vulnerabilities →