Cloud Foundation: Incorrect Implementation of Authentication Algorithm
CVE-2026-59309 is a critical-severity incorrect implementation of authentication algorithm vulnerability in Cloud Foundation from VMware, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Cloud Foundation versions: 9.1.x.x; 9.0.x.x; 5.x. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.61% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update vCenter to 9.1.0.0300 or 9.0.2.0100 or 8.0 U3k, whichever matches your release line, or a later version.
- Update Vcenter Server to 8.0 or 9.0.2.0100 or 9.1.0.0300, whichever matches your release line, or a later version.
- Read the advisory on support.broadcom.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| VMware | Cloud Foundation | 9.1.x.x; 9.0.x.x; 5.x | Not stated |
| VMware | vSphere Foundation | 9.1.x.x; 9.0.x.x | Not stated |
| VMware | vCenter | 9.1.x.x up to, but not including, 9.1.0.0300; 9.0.x.x up to, but not including, 9.0.2.0100; 8.0 up to, but not including, 8.0 U3k | 9.1.0.0300, 9.0.2.0100, 8.0 U3k |
| VMware | Telco Cloud Infrastructure | 3.0 | Not stated |
| VMware | Telco Cloud Platform | 5.1.x; 5.0.x; 4.x; 3.0 | Not stated |
| VMware | Vcenter Server | before 8.0; 8.0; 9.0 up to, but not including, 9.0.2.0100; 9.1 up to, but not including, 9.1.0.0300 | 8.0, 9.0.2.0100, 9.1.0.0300 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (vmware.com).
Official description
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: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Implementation of Authentication Algorithm
The requirements for the product dictate the use of an established authentication algorithm, but the implementation of the algorithm is incorrect.
More Incorrect Implementation of Authentication Algorithm vulnerabilities (CWE-303)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Cloud Foundation
- 2.7 Low severity
Broadcom VMWare ESX Insufficient Logging Exploited
- 9.8 Critical severity
Broadcom VMware vCenter Path Traversal Exploited
- 9.3 Critical severity
- 7.6 High severity
- 8.0 High severity
- 7.2 High severity
Recent Incorrect Implementation of Authentication Algorithm vulnerabilities
- 8.8 High severity
- 9.1 Critical severity
- 8.1 High severity
- 7.5 High severity
- 8.8 High severity
- 9.8 Critical severity
Spotted an error? Tell us.