CVE-2026-59387：Cloud Controller API 未授權存取漏洞導致特權提升

The Nginx routing configuration for Cloud Controller blocks unauthenticated access to /internal/v4/ and /internal/v5/ endpoints but omits an equivalent deny rule for /internal/v3/. As a result, the staging callback endpoints /internal/v3/staging/:guid/droplet_completed and /internal/v3/staging/:guid/build_completed are reachable from the public API listener without OAuth or mutual TLS.   An attacker with a valid build or droplet GUID can submit a forged staging callback, transition a droplet to STAGED, and persist arbitrary process metadata and sidecar data with no associated package or actor. A SpaceAuditor can enumerate GUIDs without write permissions, making this an effective privilege escalation beyond the intended role boundary.

Impact

Affected Products

The following products are affected by CVE-2026-59387 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

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Update Nginx configuration to deny unauthenticated access to /internal/v3/ endpoints.

• Add deny rule for /internal/v3/ in Nginx config.
• Restart Nginx service to apply changes.

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While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-59387 is associated with the following CWEs:

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The following table lists the changes that have been made to the CVE-2026-59387 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

• New CVE Received by [email protected]

  十月. 30, 2026

  Action	Type	Old Value	New Value
  Added	Description		The Nginx routing configuration for Cloud Controller blocks unauthenticated access to /internal/v4/ and /internal/v5/ endpoints but omits an equivalent deny rule for /internal/v3/. As a result, the staging callback endpoints /internal/v3/staging/:guid/droplet_completed and /internal/v3/staging/:guid/build_completed are reachable from the public API listener without OAuth or mutual TLS.   An attacker with a valid build or droplet GUID can submit a forged staging callback, transition a droplet to STAGED, and persist arbitrary process metadata and sidecar data with no associated package or actor. A SpaceAuditor can enumerate GUIDs without write permissions, making this an effective privilege escalation beyond the intended role boundary.
  Added	CVSS V3.1		AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
  Added	Affected		New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/59xxx/CVE-2026-59387.json">CVE-2026-59387</a>
  Added	Reference		https://www.cloudfoundry.org/blog/cve-2026-59387-broken-access-control-restriction-in-cloud-controller-api/

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.