Vulnerabilities

Vulnerability · CVE-2017-4940

The ESXi Host Client in VMware ESXi (6.5 before ESXi650-201712103-SG, 5.5 before ESXi600-201711103-SG and 5.5 before ESXi550-201709102-SG) contains a vulnerability tha…

Published Dec 20, 2017 · catalog updated Jun 17, 2026 · the affected product

Last checked Nov 7, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2017-4940. EPSS is 0.91%. Act only if a listed version of the affected product is installed.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium6.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.91%
Remediation
Advisory link
Affected products
cpe vmware/esxi

The ESXi Host Client in VMware ESXi (6.5 before ESXi650-201712103-SG, 5.5 before ESXi600-201711103-SG and 5.5 before ESXi550-201709102-SG) contains a vulnerability that may allow for stored cross-site scripting (XSS). An attacker can exploit this vulnerability by injecting Javascript, which might get executed when other users access the Host Client.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe vmware/esxi5.5

How to fix CVE-2017-4940

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2017-4940. EPSS is 0.91%. Act only if a listed version of the affected product is installed.

Which versions are affected?

Compare what you have installed with 5.5. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-79: Cross-site Scripting (XSS). EPSS 0.91%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 20, 2017 · Monitored products — critical

    Detected

    The ESXi Host Client in VMware ESXi (6.5 before ESXi650-201712103-SG, 5.5 before ESXi600-201711103-SG and 5.5 before ESXi550-201709102-SG) contains a vulnerability that may allow for stored cross-site scripting (XSS). An attacker can exploit this vulnerability by injecting Javascript, which might get executed when other users access the Host Client.

  2. Jun 17, 2026 · Monitored products — critical

    Updated

    The ESXi Host Client in VMware ESXi (6.5 before ESXi650-201712103-SG, 5.5 before ESXi600-201711103-SG and 5.5 before ESXi550-201709102-SG) contains a vulnerability that may allow for stored cross-site scripting (XSS). An attacker can exploit this vulnerability by injecting Javascript, which might get executed when other users access the Host Client.

Sources

  • CVE.orgVulnerability recordCVE-2017-4940

    Official CVE identifier

    cve.org
  • Monitored products — criticalVendor advisoryCVE-2017-4940

    The ESXi Host Client in VMware ESXi (6.5 before ESXi650-201712103-SG, 5.5 before ESXi600-201711103-SG and 5.5 before ESXi550-201709102-SG) contains a vulnerability that may allow for stored cross-site scripting (XSS). An attacker can exploit this vulnerability by injecting Javascript, which might get executed when other users access the Host Client.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • Monitored products — criticalNov 4, 2026
  • CVE.orgNov 2, 2026