CVE-2026-25958: Cube Privilege Escalation Vulnerability

CVE-2026-25958 Overview

CVE-2026-25958 is a privilege escalation vulnerability in Cube, a semantic layer for building data applications. The vulnerability affects versions from 0.27.19 to before 1.5.13, 1.4.2, and 1.0.14. An attacker with a valid API token can craft a specially designed request that leads to privilege escalation, potentially gaining unauthorized access to sensitive data and elevated permissions within the Cube environment.

Critical Impact

This vulnerability allows authenticated users to escalate their privileges through crafted API requests, potentially compromising data confidentiality across the entire Cube deployment.

Affected Products

• Cube versions from 0.27.19 to before 1.0.14
• Cube versions from 0.27.19 to before 1.4.2
• Cube versions from 0.27.19 to before 1.5.13

Discovery Timeline

• 2026-02-09 - CVE CVE-2026-25958 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2026-25958

Vulnerability Analysis

This vulnerability is classified under CWE-807 (Reliance on Untrusted Inputs in a Security Decision). The flaw exists in how Cube processes API requests from authenticated users. When a specially crafted request is submitted with a valid API token, the application fails to properly validate the authorization boundaries, allowing the requester to elevate their privileges beyond their intended scope.

The network-accessible nature of this vulnerability means it can be exploited remotely by any authenticated user with a valid API token. The attack requires low privilege access to initiate but can result in unauthorized access to highly confidential data across tenant boundaries in multi-tenant deployments.

Root Cause

The root cause stems from CWE-807: Reliance on Untrusted Inputs in a Security Decision. The Cube API improperly trusts certain input parameters when making authorization decisions, allowing authenticated users to manipulate these inputs to gain access to resources or functionality beyond their authorized scope. This architectural flaw in the trust boundary validation enables privilege escalation through parameter manipulation.

Attack Vector

The attack vector is network-based with low complexity. An attacker must possess a valid API token (low privilege requirement) but can exploit the vulnerability without any user interaction. The scope is changed, meaning the vulnerability can affect resources beyond its original security scope, leading to high confidentiality impact on data the attacker should not have access to.

The attack flow typically involves:

1. Authenticating with a valid but low-privilege API token
2. Crafting a malicious API request with manipulated authorization parameters
3. Submitting the request to gain elevated access to protected resources
4. Exfiltrating sensitive data from unauthorized contexts

For detailed technical information about the exploitation mechanism, refer to the GitHub Security Advisory.

Detection Methods for CVE-2026-25958

Indicators of Compromise

• Unusual API request patterns from low-privilege tokens accessing high-privilege resources
• Anomalous data access patterns where users query data outside their normal scope
• API requests containing manipulated or unexpected authorization parameters
• Increased volume of API calls from single tokens to multiple tenant contexts

Detection Strategies

• Implement API request logging and analyze for privilege boundary violations
• Monitor for API tokens being used to access resources inconsistent with their assigned permissions
• Deploy anomaly detection on user behavior patterns within Cube deployments
• Review authentication logs for tokens accessing cross-tenant or administrative resources

Monitoring Recommendations

• Enable detailed audit logging for all Cube API operations
• Configure alerts for privilege escalation patterns in API access logs
• Monitor for rapid enumeration attempts across data models or tenants
• Implement real-time monitoring of security context changes in API requests

How to Mitigate CVE-2026-25958

Immediate Actions Required

• Upgrade Cube to patched versions: 1.5.13, 1.4.2, or 1.0.14 depending on your version branch
• Audit API token usage to identify any potential exploitation
• Review access logs for signs of privilege escalation attempts
• Temporarily restrict API access if immediate patching is not possible

Patch Information

The vulnerability is fixed in Cube versions 1.5.13, 1.4.2, and 1.0.14. Organizations should upgrade to the appropriate patched version based on their current deployment:

• For 1.5.x deployments: Upgrade to 1.5.13 or later
• For 1.4.x deployments: Upgrade to 1.4.2 or later
• For 1.0.x deployments: Upgrade to 1.0.14 or later

Refer to the GitHub Security Advisory for complete patch details.

Workarounds

• Implement additional authorization checks at the network layer or API gateway level
• Restrict API token issuance and implement stricter token rotation policies
• Use network segmentation to limit access to Cube API endpoints
• Deploy Web Application Firewall (WAF) rules to inspect and filter malicious API requests

# Example: Restrict Cube API access via firewall rules
# Allow only trusted IP ranges to access Cube API endpoints
iptables -A INPUT -p tcp --dport 4000 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 4000 -j DROP