CVE-2026-4982: Venueless Information Disclosure Flaw

CVE-2026-4982 Overview

CVE-2026-4982 is an authorization bypass vulnerability in Venueless, an open-source virtual event platform. A user with the "update world" permission in any Venueless world can exploit a bug in the reporting feature to exfiltrate chat messages from direct messages or channels in other worlds on the same server. This cross-world data access represents a significant breach of the expected isolation boundaries between separate virtual event spaces.

The exploitability of this vulnerability is limited by the fact that the attacker needs to know the internal channel UUID of the target chat channel. This UUID is unlikely to be obtained by an outside attacker, especially for direct messages, which provides some natural mitigation against opportunistic attacks.

Critical Impact

Attackers with limited permissions in one virtual event world can access private communications from entirely separate worlds on the same server, potentially exposing sensitive business discussions, personal messages, and confidential event communications.

Affected Products

• Venueless (versions prior to security patch)
• Self-hosted Venueless server instances with multiple worlds configured
• Venueless deployments where users have "update world" permissions

Discovery Timeline

• 2026-03-27 - CVE CVE-2026-4982 published to NVD
• 2026-03-30 - Last updated in NVD database

Technical Details for CVE-2026-4982

Vulnerability Analysis

This vulnerability stems from improper input validation (CWE-20) in the Venueless reporting feature. The reporting functionality, designed to allow users to flag inappropriate content for moderation, fails to properly validate that the reported content belongs to the same world where the reporting user has permissions.

When a user with "update world" permission initiates a report action, the system processes the request without verifying that the channel UUID provided in the request corresponds to a channel within the user's authorized world. This architectural oversight allows an attacker to specify arbitrary channel UUIDs from other worlds on the same server, effectively bypassing the intended world-level access controls.

The vulnerability requires network access and low-privileged authentication (the "update world" permission), but does require some level of attack preparation to obtain valid channel UUIDs from other worlds.

Root Cause

The root cause is insufficient authorization validation in the reporting feature's backend implementation. The system correctly authenticates the user and verifies they have "update world" permission, but fails to perform a critical secondary check: ensuring the target channel belongs to the world where the user holds that permission. This represents a classic broken access control pattern where permissions are checked at one level but not properly scoped to the intended resources.

Attack Vector

The attack vector is network-based and requires the following conditions:

1. The attacker must have a valid account on the Venueless server
2. The attacker must possess the "update world" permission in at least one world
3. The attacker must obtain the internal channel UUID of a target channel in another world
4. The attacker crafts a malicious report request targeting the cross-world channel

The attack exploits the reporting feature by submitting a report with a channel UUID from a different world. Instead of rejecting this cross-world reference, the vulnerable system retrieves and exposes the chat messages from the unauthorized channel as part of the report context. This could include private direct messages and channel conversations that the attacker should have no access to view.

For technical details on the vulnerability mechanism, refer to the GitHub Security Advisory.

Detection Methods for CVE-2026-4982

Indicators of Compromise

• Unusual report submissions from users referencing channel UUIDs not associated with their authorized worlds
• Elevated volume of report requests from a single user or account
• Report requests containing channel UUIDs that do not exist in the requesting user's world
• Access patterns showing a user requesting data from multiple worlds despite limited permissions

Detection Strategies

• Implement logging that captures the world context of both the reporting user and the target channel for each report request
• Create alerts for report requests where the channel world ID does not match the user's authorized world
• Monitor for users with "update world" permissions making abnormally high numbers of report requests
• Deploy application-level monitoring to detect cross-world resource access attempts

Monitoring Recommendations

• Enable detailed audit logging for all reporting feature API endpoints
• Implement real-time alerting on authorization boundary violations
• Review historical report logs for evidence of exploitation attempts
• Monitor for reconnaissance activity attempting to enumerate channel UUIDs

How to Mitigate CVE-2026-4982

Immediate Actions Required

• Review and update Venueless to the latest patched version
• Audit users with "update world" permissions and reduce where possible
• Review report logs for any suspicious cross-world access attempts
• Consider temporarily disabling the reporting feature if a patch is not immediately available

Patch Information

The Venueless development team has addressed this vulnerability through a security update. Administrators should update their Venueless installations to the latest available version that includes the fix for this authorization bypass. Refer to the GitHub Security Advisory for specific version information and patch details.

Workarounds

• Restrict "update world" permissions to only highly trusted administrators
• Implement network-level segmentation to isolate critical worlds on separate server instances
• Deploy a Web Application Firewall (WAF) rule to inspect and validate channel UUIDs in report requests
• Consider running sensitive worlds on dedicated Venueless instances rather than multi-tenant configurations

# Configuration example
# Review users with elevated permissions in Venueless
# Check your Venueless admin panel or database for users with "update world" permission
# Revoke permissions from users who do not require them

# If using Docker, update to latest version:
docker pull venueless/venueless:latest
docker-compose down && docker-compose up -d

# Review application logs for suspicious activity:
grep -i "report" /var/log/venueless/application.log | grep -v "world_match"