CVE-2026-69114 in Server
Summary
by MITRE • 08/10/2026
Spacebar Server before commit 8d126f4 contains a cross-channel message deletion vulnerability in the single-delete and bulk-delete message handlers that fail to scope message queries to the requested channel. Authenticated users with MANAGE_MESSAGES permission in any controlled channel can delete arbitrary messages in other channels by routing delete requests through their own channel.
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Analysis
by VulDB Data Team • 08/10/2026
This vulnerability exists within the Spacebar Server messaging platform prior to commit 8d126f4 and represents a critical authorization bypass flaw that enables authenticated users to perform unauthorized message deletion across different communication channels. The core technical issue stems from improper input validation and query scoping within the message deletion handlers, specifically affecting both single-message and bulk-delete operations. When users with MANAGE_MESSAGES permissions submit delete requests, the system fails to properly validate that the requested messages belong to the channel through which the request is being made, creating a cross-channel scope leakage vulnerability.
The operational impact of this vulnerability is significant as it allows malicious actors or compromised accounts with relatively low-level permissions to manipulate message content across multiple channels within the same server. An authenticated user can exploit this weakness by crafting delete requests that target messages in other channels, effectively bypassing the intended channel boundaries and access controls. This creates a scenario where users can remove critical information, evidence of conversations, or sensitive data from channels they do not directly control, potentially leading to data loss, information tampering, and disruption of communication flows.
The vulnerability aligns with CWE-639 Access Control Bypass, which specifically addresses situations where applications fail to properly validate user permissions across different resources or scopes. From an adversarial perspective, this flaw maps to ATT&CK technique T1485 Data Destruction, as it enables unauthorized modification of data within communication channels, and T1078 Valid Accounts, since the exploitation requires only legitimate authentication credentials with existing permissions. The security implications extend beyond simple message deletion to encompass potential information warfare scenarios where attackers could systematically remove evidence from multiple channels or disrupt ongoing communications by deleting critical messages.
The root cause of this vulnerability lies in the implementation of the message deletion handlers which fail to properly bind user requests to specific channel contexts during query execution. This architectural flaw demonstrates a lack of proper parameter validation and resource scoping mechanisms that should ensure all operations are constrained to the authenticated user's designated access boundaries. To address this issue, developers must implement robust input validation that explicitly verifies channel ownership and implements strict scope enforcement for all message operations, ensuring that delete requests can only affect messages within the requesting user's authorized channel context.
Mitigation strategies should include immediate implementation of proper query scoping mechanisms that validate channel membership before executing any deletion operations, along with comprehensive code reviews to identify similar patterns across other message handling functions. Additionally, system administrators should implement monitoring solutions that track unusual deletion patterns across channels and consider implementing rate limiting on bulk delete operations to prevent rapid mass deletions. The fix requires modification of the backend message handler logic to ensure all delete requests include explicit channel context validation and proper access control checks before any database queries are executed against message records.