CVE-2026-59387

HIGH CVSS 8.8 PoC Available
Published: 2026-10-30
Modified: 2026-10-30
Enriched via mock
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AI Threat Summary

CVE-2026-59387 is a high-severity vulnerability with a CVSS score of 8.8 affecting the target software. Authentication can be bypassed allowing unauthenticated access. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.

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.

Attack Chain
1
Reconnaissance

Attacker identifies authentication endpoint and tests for bypass conditions

2
Initial Access

Attacker exploits CVE-2026-59387 authentication flaw to gain unauthorized access without valid credentials

3
Discovery

Attacker enumerates accessible resources, users, and configurations

4
Collection

Attacker exfiltrates sensitive data accessible without proper authorization

MITRE ATT&CK Techniques
T1078 Valid Accounts
Initial Access

Authentication bypass grants attacker access as legitimate user

T1548 Abuse Elevation Control Mechanism
Privilege Escalation

Bypassed auth may grant elevated or admin-level permissions

Indicators of Compromise
Type Value Description
user_agent Mozilla/5.0 (compatible; exploit/1.0) Generic exploit scanner user agent pattern
url /api/vuln-endpoint?payload=<malicious> Exploit attempt against application endpoint — monitor access logs for anomalous params
Remediation
1. Apply vendor-supplied security patches immediately. 2. If patches are unavailable, apply recommended mitigations from the vendor advisory. 3. Enable WAF rules or IDS signatures to detect exploitation attempts. 4. Monitor logs for indicators of compromise listed above. 5. Implement network segmentation to limit blast radius if exploitation occurs. 6. Subscribe to vendor security advisories for this product.
Quick Facts
CVE ID CVE-2026-59387
CVSS Score 8.8
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published 2026-10-30
Exploited No
CISA KEV No
PoC Available
References
External Resources
NVD Entry BleepingComputer The Hacker News