CVE-2026-63749 in SurrealDB
Summary
by MITRE • 07/20/2026
SurrealDB versions before 3.1.0 contain an authentication bypass vulnerability in LIVE SELECT subscriptions where permission expressions referencing $value, $before, $after, or $event are evaluated against attacker-controlled bindings instead of actual documents. Authenticated subscribers can bind chosen values to these parameter names and register LIVE SELECT queries to receive notifications for records that SELECT permission expressions should have hidden.
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Analysis
by VulDB Data Team • 07/20/2026
This vulnerability exists in SurrealDB versions prior to 3.1.0 and represents a critical authentication bypass flaw affecting the LIVE SELECT subscription mechanism. The core issue stems from improper evaluation of permission expressions within the database's access control system where specific parameters such as $value, $before, $after, and $event are processed against attacker-controlled bindings rather than actual document contents. This fundamental flaw allows malicious actors to manipulate the permission checking logic by directly binding arbitrary values to these reserved parameter names during subscription registration.
The technical implementation of this vulnerability occurs within the database's query execution engine where LIVE SELECT operations are processed. When users register subscriptions with permission expressions that reference these special parameters, the system incorrectly resolves their values from user-controlled bindings instead of extracting them from the actual documents being monitored. This misinterpretation enables attackers to craft malicious subscription requests that can bypass intended access restrictions and receive notifications for records that should remain hidden based on normal permission rules.
The operational impact of this vulnerability is severe as it allows authenticated users to gain unauthorized visibility into data they should not be able to access. Attackers can leverage this flaw to subscribe to LIVE SELECT queries with crafted permission expressions that reference attacker-controlled values, effectively circumventing the database's built-in access control mechanisms. This creates a persistent surveillance capability where malicious subscribers can monitor changes to records that would normally be protected by their access policies, potentially exposing sensitive information or enabling further attacks through data exfiltration.
The vulnerability aligns with CWE-284 Access Control Bypass and maps to ATT&CK technique T1078 Valid Accounts for privilege escalation. Database systems typically rely on proper access control evaluation to maintain data integrity and confidentiality, but this flaw fundamentally undermines those protections by allowing parameter manipulation during subscription registration. Organizations using affected SurrealDB versions face significant risk of unauthorized data exposure and potential compliance violations, particularly in environments where strict data access controls are required.
Mitigation strategies should include immediate upgrade to SurrealDB version 3.1.0 or later where this vulnerability has been addressed through proper parameter resolution logic. Administrators should also implement network-level restrictions to limit access to database subscription endpoints and monitor for unusual subscription patterns that might indicate exploitation attempts. Additionally, organizations should review their existing LIVE SELECT subscriptions to ensure no malicious bindings have been established and consider implementing additional monitoring for unauthorized access patterns in their database access logs.