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Cloud Foundry UAA EUVDEUVD-2026-76026

| CVE-2026-47839 CRITICAL
Improper Access Control (CWE-284)
2026-09-11 vmware GHSA-9wp3-mffv-5vr4
9.2
CVSS 4.0 · Vendor: vmware
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Authenticate via federated OIDC provider
  2. Delivery
    IdP asserts group claims
  3. Exploit
    UAA AS_SCOPES + wildcard whitelist maps groups to scopes
  4. Execution
    uaa.admin granted in token
  5. Impact
    Full administrative control of UAA

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Access control enforcement
MITRE ATT&CK

1 technique across 1 tactic: Defense Evasion

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires the target UAA to have a federated OIDC identity provider configured with groupMappingMode: AS_SCOPES AND a wildcard ('*') entry in that provider's externalGroupsWhitelist - this is the explicit prerequisite stated in the description and is not the default configuration. The attacker must be able to authenticate through that federated OIDC provider (i.e. be a valid user of the external IdP, or control/influence the group claims it asserts). Limiting factors: the specific AS_SCOPES + wildcard combination is non-default (reflected as AC:H/AT:P in the CVSS 4.0 vector); deployments using explicit group whitelists or internal group mapping are not exploitable.

Impact

The CVSS 4.0 score of 9.2 reflects network attack vector (AV:N), no privileges on UAA itself (PR:N), no user interaction (UI:N), and full compromise of confidentiality, integrity and availability of the UAA control plane (VC:H/VI:H/VA:H) - obtaining uaa.admin effectively grants control of identity and token issuance across the foundation. Crucially the vector also encodes AC:H and AT:P, meaning exploitation is not trivial: it depends on a specific present condition (the AS_SCOPES + wildcard whitelist configuration), which is not UAA's default. There is no EPSS or KEV signal supplied and no POC referenced, so there is no evidence of active exploitation - this is a high-impact-but-conditionally-exploitable issue. For environments that happen to run the vulnerable configuration the real-world risk is severe (full admin takeover); for everyone else it is latent. The input 'Information Disclosure' tag understates the impact, which is privilege escalation to platform admin.

Exploit ScenarioDerived

An enterprise federates an external OIDC identity provider into UAA using groupMappingMode: AS_SCOPES and sets externalGroupsWhitelist to '*' for convenience. A user in the external directory (or someone who can influence their group claims) authenticates through that provider and receives a token carrying uaa.admin, gaining administrative control over UAA and the Cloud Foundry foundation. No public exploit code is identified at time of analysis; the attack relies on the misconfiguration being present.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
No patch listed yet 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 11, 2026

Privilege escalation in Cloud Foundry UAA (User Account and Authentication server) lets users who authenticate via a federated OIDC provider obtain the powerful uaa.admin scope even though operators intended to restrict that provider using the externalGroupsWhitelist configuration. The flaw manifests only when an OIDC identity provider is configured with groupMappingMode: AS_SCOPES together with a wildcard (*) externalGroupsWhitelist entry, causing the wildcard to grant all mapped external groups as scopes - including uaa.admin. No public exploit has been identified at time of analysis, and the vulnerability requires a specific non-default IdP configuration.

RemediationAI

Consult the Cloud Foundry advisory (https://www.cloudfoundry.org/blog/cve-2026-47839-federated-oidc-users-can-bypass-externalgroupswhitelist-to-gain-uaa-admin/) and upgrade UAA / cf-deployment to the patched release it specifies; no exact fixed version is included in the supplied data, so the patched version should be confirmed against that advisory. As an immediate compensating control, replace any wildcard ('*') entry in externalGroupsWhitelist for OIDC providers using groupMappingMode: AS_SCOPES with an explicit allow-list of only the specific external groups that should map to scopes - the trade-off is you must enumerate and maintain the exact group set, but this prevents uaa.admin from being granted implicitly. Alternatively, switch the affected provider away from AS_SCOPES to internal group mapping if that fits your authorization model. After remediation, audit existing tokens and users granted uaa.admin for any unauthorized escalation that may already have occurred.

Affected VersionsENISA

UAA 0 ≤77.30.0
cf-deployment 0 ≤48.9.0

Affected Packages

euvd cf_deployment no fix
euvd uaa no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

UAA is the OAuth2/OIDC authorization server used across Cloud Foundry (shipped via cf-deployment) to issue tokens and enforce scopes for the platform. When an external OIDC identity provider is federated into UAA, operators map the provider's group claims into UAA using groupMappingMode. In AS_SCOPES mode, groups asserted by the external IdP are treated directly as UAA scopes rather than mapped through internal group membership, and externalGroupsWhitelist is meant to constrain which external groups are accepted. A wildcard ('*') whitelist entry combined with AS_SCOPES causes UAA to accept every external group as a scope without filtering, so an attacker-controlled or misassigned group claim resolves to uaa.admin. Although NVD lists no CWE, the root cause is an authorization/access-control defect (improper privilege management / improper authorization, CWE-269/CWE-863) rather than information disclosure as the input tag suggests.

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Severity by source

Vendor (vmware) PRIMARY 9.2 CRITICAL
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
vuln.today AI 8.1 HIGH

Remote OIDC user needs no UAA privileges (PR:N) but exploitation depends on a specific non-default AS_SCOPES+wildcard configuration (AC:H); uaa.admin grants full C/I/A of the UAA control plane.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
4.0 AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (vmware).

CVSS VectorVendor: vmware

Attack Vector
Network
Attack Complexity
High
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
High
Vulnerable system: Availability
High
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

A vulnerability allows users authenticating through a federated OIDC provider to obtain the uaa.admin scope despite operators restricting that provider through externalGroupsWhitelist configuration. The issue occurs specifically when an OIDC identity provider uses groupMappingMode: AS_SCOPES with a wildcard externalGroupsWhitelist entry.

Executive ViewAI

Why It Matters

Cloud Foundry's UAA authentication server contains a privilege escalation flaw allowing federated OIDC users to illegally obtain administrator-level access when specific group-mapping configurations are enabled, potentially compromising all user accounts and authentication infrastructure organization-wide.

Business Impact: Severe
Compensating Controls

No vendor-released patch identified at time of analysis. For vulnerable configurations (groupMappingMode: AS_SCOPES with wildcard externalGroupsWhitelist): Replace wildcard group mappings with explicit external group-to-scope mappings that exclude administrative scopes; disable AS_SCOPES mode if not operationally required; restrict OIDC federation to non-interactive service accounts only; audit UAA token logs to detect unexpected admin-scope grants to federated identities; implement privileged request approval workflows.

Threat Intelligence Overview

EPSS Score
0.3%
Top 76% exploitable
Prevalence
Medium
Cloud Foundry UAA is common in enterprise PaaS but not universally deployed
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.3%
Patch available No
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
Very High
Technical Impact
Total

Priority Score

46
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +46
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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