dbcve.org
Information ExposureWeakness · CWE-200

CVE-2026-40965

CRITICAL · 10.0 CVSS v3.1 Published 2026-06-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Cloud Foundry UAA versions v76.12.0 through v78.12.0 are vulnerable to a private key exposure. The server contains a vulnerability where EC (Elliptic Curve) private keys are inadvertently exposed through the public /token_keys endpoint. This endpoint is designed to provide public key material for JWT token verification but incorrectly exposes private key components for EC keys. The vulnerability affects deployments using EC keys for JWT token signing. The vulnerability does not affect RSA key configurations, only deployments using EC keys for JWT signing. Affected versions: - uaa_release: v76.12.0 through v78.12.0 (inclusive); fixed in v78.13.0 or later - CF Deployment: v30.0.0 through v56.0.0 (inclusive); fixed in v56.1.0 or later (bundles uaa_release v78.13.0)

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Cloud Foundry UAA contains a private key exposure vulnerability where the /token_keys endpoint inadvertently exposes EC (Elliptic Curve) private key components instead of only public key material. Attackers can obtain private keys from this public endpoint and potentially forge JWT tokens for authentication bypass.

MitigationUpgrade uaa_release to v78.13.0 or later, or CF Deployment to v56.1.0 or later, to remediate the EC private key exposure in the /token_keys endpoint.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check UAA version against affected range
    Query the UAA version using 'uaac target' and 'uaac context' or check via BOSH 'bosh vms -d deployment cf' and inspect the UAA job. Compare the installed version to v76.12.0 through v78.12.0.
    Affected if The installed UAA version falls within v76.12.0 through v78.12.0 (inclusive).
  2. Verify EC keys are configured in UAA
    Check UAA configuration files (typically in /etc/uaa or via 'uaac token key') for JWT signing key configurations. Look for 'key' entries with algorithm 'EC' or 'ES256'/'ES384'/'ES512'.
    Affected if UAA is configured to use EC (Elliptic Curve) keys for JWT signing.
  3. Inspect /token_keys endpoint for private key exposure
    Make a GET request to the public /token_keys endpoint (e.g., 'curl https://uaa.[system-domain]/token_keys'). For each EC key entry, verify that only public key components are present (should contain 'crv', 'x', 'y').
    Affected if The response contains EC private key components - specifically the 'd' parameter is visible in any key entry, indicating private key material is exposed.

You are affected if UAA version is between v76.12.0 and v78.12.0 inclusive AND EC keys are configured AND the /token_keys endpoint exposes the 'd' parameter for EC keys.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade uaa_release to v78.13.0 or later, or CF Deployment to v56.1.0 or later, to remediate the EC private key exposure in the /token_keys endpoint.

Recommended fix High confidence

uaa_release v78.13.0 or later / CF Deployment v56.1.0 or later

  1. Upgrade uaa_release from v76.12.0-v78.12.0 to v78.13.0 or later
  2. If using CF Deployment, upgrade from v30.0.0-v56.0.0 to v56.1.0 or later (this bundles the fixed uaa_release v78.13.0)
  3. After upgrade, verify the /token_keys endpoint no longer exposes EC private key components
  4. Confirm JWT token validation still works correctly with the corrected public key data

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-40965 in production — separate from our analysis above.

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