Description

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.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.5",
  "pubDate": "2026-08-10T20:17:32.010Z",
  "pubdate": "2026-08-10T20:17:32.010Z",
  "executiveSummary": "Spacebar Server before commit 8d126f4 suffers from a cross-channel message deletion vulnerability residing in the single-delete and bulk-delete message handlers.\nThe flaw allows authenticated users who possess the MANAGE_MESSAGES permission in any controlled channel to delete arbitrary messages located in completely different, unauthorized channels.\nThe impact of this vulnerability is significant, as it enables malicious actors with minimal privileges to cause severe data loss, disrupt communications, and compromise the integrity of chat environments across the affected system.\nExploitation of this security issue requires authentication and the specific MANAGE_MESSAGES capability within at least one channel, allowing the attacker to route crafted delete requests through their authorized context to target arbitrary resources.",
  "technicalDetails": "The root cause of the vulnerability stems from inadequate input validation and missing authorization checks within the single-delete and bulk-delete message handlers of Spacebar Server before commit 8d126f4.\nSpecifically, the affected codebase fails to properly scope message database queries to the requested channel context during deletion routines.\nWhen processing delete requests, the application trusts the provided message identifiers without verifying whether the targeted messages actually reside within the channel where the user holds the requisite permissions.\nThe attack flow proceeds as follows: an authenticated attacker identifies or guesses message identifiers from other channels. The attacker then issues a single-delete or bulk-delete request originating from a channel where they possess the MANAGE_MESSAGES permission.\nBecause the backend message handlers omit channel-scoping constraints in their database queries, the application executes the deletion against the specified message identifiers globally or across unauthorized channel boundaries.\nThis missing scoping logic permits privilege escalation regarding message management actions, enabling horizontal unauthorized data destruction.\nAffected versions include all Spacebar Server deployments prior to commit 8d126f4.\nThe vulnerability is exploitable by any authenticated user meeting the baseline permission requirement of MANAGE_MESSAGES in any arbitrary channel within the network exposure boundary of the server."
}