dbcve.org
Improper AuthenticationWeakness · CWE-287

CVE-2026-40964

HIGH · 7.5 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 →
84/100
Remediation priority · High
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
Authentication Bypass in cf-auth-proxy in Cloud Foundry Foundation all installations allows an unauthenticated remote attacker to gain read access to every log and metric for every application and platform component via minting a JWT that the cf-auth-proxy accepts as a valid logs.admin token. Affected versions: - log-cache_release: all versions through v3.2.6 (inclusive); fixed in v3.2.7 or later - CF Deployment: all versions through v55.?.0 (inclusive); fixed in v55.?.0 or later (bundles log-cache_release v3.2.7)

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

Authentication bypass in Cloud Foundry's cf-auth-proxy allows attackers to forge JWT tokens that are incorrectly accepted as valid logs.admin tokens, bypassing authentication and granting unauthorized read access to all application and platform logs/metrics.

MitigationUpgrade log-cache_release to v3.2.7 or later, or CF Deployment to the version that bundles the fixed log-cache_release.

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
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

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. Identify cf-auth-proxy deployment
    Search for cf-auth-proxy processes or containers in your environment using 'ps aux | grep cf-auth-proxy' or 'kubectl get pods | grep auth-proxy' (or your container orchestrator's equivalent command)
    Affected if cf-auth-proxy is present in your environment
  2. Determine log-cache release version
    Run 'cf curl /v2/products' to find the log-cache product, then check the installed version via your Cloud Foundry deployment manifest or 'bosh releases | grep log-cache'. Alternatively, check the cf-auth-proxy binary version with '--version' flag if accessible
    Affected if version is lower than v3.2.7 (or unknown and cannot be verified as v3.2.7 or later)
  3. Verify JWT validation configuration
    Inspect the cf-auth-proxy configuration files for the 'jwt' section. Look for the 'public_key' or 'verification_key' setting. Check if a static or insecure key is configured that could be leveraged to forge tokens
    Affected if a hardcoded or guessable JWT public key is configured, or no proper signature validation is enforced
  4. Test authentication bypass
    Send an unauthenticated HTTP request to the cf-auth-proxy logs endpoint (e.g., curl -k https://<proxy-host>/api/v1/read/logs) without any Authorization header. Also try with a self-crafted JWT containing 'logs.admin': true in the payload
    Affected if the request returns log data or metrics without returning a 401/403 authentication error

You are affected if cf-auth-proxy is deployed and responds to log/metric read requests without requiring valid authentication, or if the installed version cannot be confirmed as v3.2.7 or later.

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 log-cache_release to v3.2.7 or later, or CF Deployment to the version that bundles the fixed log-cache_release.

Recommended fix High confidence

log-cache_release v3.2.7 or later; CF Deployment v55.x.0 or later (bundling log-cache_release v3.2.7)

  1. Upgrade log-cache_release to version v3.2.7 or later
  2. If using CF Deployment, upgrade to version v55.x.0 or later that bundles log-cache_release v3.2.7
  3. After upgrading, verify that cf-auth-proxy properly validates JWT tokens and rejects invalid/minted tokens
  4. Review access logs to confirm the authentication bypass vulnerability is no longer exploitable
Caveat Review the log-cache_release and CF Deployment v55.x.0 release notes for any breaking changes before upgrading

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
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2026-40964 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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