CVE-2026-56654 in Gitea
Summary
by MITRE • 08/13/2026
Privilege Escalation via Access Token Scope Escalation in API
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Analysis
by VulDB Data Team • 08/13/2026
This vulnerability represents a critical privilege escalation opportunity within application programming interfaces where an attacker can manipulate access token scopes to gain elevated permissions beyond their intended authorization levels. The flaw typically occurs when api implementations fail to properly validate or enforce scope boundaries during token processing, allowing malicious actors to exploit insufficient access control mechanisms. Such vulnerabilities are particularly dangerous in modern cloud environments and microservices architectures where apis serve as primary communication channels between different system components and external entities.
The technical root cause of this vulnerability stems from inadequate scope validation within the authentication and authorization frameworks governing api access tokens. When applications issue tokens with overly broad scopes or fail to enforce strict scope boundaries during token consumption, attackers can manipulate token claims or exploit implementation gaps in scope verification processes. This often manifests through improper handling of scope inheritance, missing scope validation checks, or flawed token refresh mechanisms that preserve elevated privileges across authentication cycles. The vulnerability directly aligns with cwe-264 permissions, privileges, and access controls weakness category, specifically addressing insufficient enforcement of authorization boundaries.
Operational impact of this vulnerability extends far beyond simple unauthorized data access, potentially enabling complete system compromise through lateral movement and privilege escalation chains. Attackers can leverage these tokens to access sensitive resources, modify system configurations, escalate their privileges to administrative levels, or even pivot to other systems within the network perimeter. The implications are particularly severe in multi-tenant environments where a compromised token could provide access to multiple customer accounts or organizational data sets. This vulnerability significantly increases attack surface and can facilitate advanced persistent threat campaigns where adversaries maintain long-term access through elevated privileges.
Mitigation strategies must address both immediate remediation and architectural improvements within api security frameworks. Organizations should implement strict scope validation mechanisms that enforce least privilege principles, regularly audit token scopes for unnecessary permissions, and establish robust token lifecycle management processes including proper revocation and refresh controls. Implementation of oauth 2.0 best practices with explicit scope definitions and mandatory scope verification checks forms the foundation of defense. Additionally, continuous monitoring of token usage patterns and implementation of automated detection systems for scope anomalies can help identify potential exploitation attempts. Security controls should also include regular penetration testing of api endpoints to validate scope enforcement mechanisms, while adherence to industry standards such as nist 800-53 security controls and iso 27001 information security management requirements provides comprehensive framework guidance for addressing these access control weaknesses.