VMware

CVE-2026-59309: vCenter authentication-bypass vulnerability

Is it exploited?

Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of 29 Oct 2026.

VulnCheck KEV lists it since 14 Aug 2026. It cites 1 public report, the first from 14 Aug 2026.

medium.com

How likely is exploitation in the next 30 days?

0.6%

EPSS score, percentile 49.2 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

9.8 Critical

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

9.1.x.x
9.0.x.x
5.x
9.1.x.x
9.0.x.x
from 9.1.x.x to before 9.1.0.0300

and 7 more in the table below

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; VulnCheck KEV, as of 30 Oct 2026; FIRST EPSS, as of 30 Oct 2026; CVE List, as of 30 Oct 2026. About the data.

Description

vCenter authentication-bypass vulnerability

VMware vCenter contains an authentication bypass vulnerability in the VMware Directory Service. A malicious actor with network access to vCenter may exploit this issue to bypass authentication and gain unauthorized access to the system.

Source: CVE List, as of 30 Oct 2026. About the data.

What to do

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

This summary is based on the CVE record as of 30 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.