CVE-2026-4982 is a vulnerability identified in the pretix Venueless platform, specifically related to improper input validation (CWE-20) within its reporting feature. The flaw allows an authenticated user possessing the "update world" permission in any given Venueless world to exfiltrate chat messages from direct messages or channels belonging to other worlds hosted on the same server. This occurs because the reporting feature does not adequately validate input parameters, enabling cross-world data leakage. The exploit requires the attacker to know the internal channel UUID of the target chat channel, which is a unique identifier not typically exposed externally, especially for direct messages, thus limiting the attack surface primarily to insiders or users with elevated knowledge. The vulnerability affects version 0.0.0 of Venueless and was published on March 27, 2026. The CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H) indicates network attack vector, low attack complexity, partial authentication required, no user interaction, and high impact on confidentiality, with scope and integrity impacts also high, and security requirements high. No patches or known exploits in the wild are currently reported, but the risk remains significant due to the sensitive nature of chat data and the potential for insider misuse.

The primary impact of CVE-2026-4982 is the unauthorized disclosure of sensitive chat messages across different worlds within the same Venueless server. This can lead to breaches of confidentiality, exposing private communications including direct messages and channel discussions. For organizations relying on Venueless for event management or community engagement, this could result in reputational damage, loss of user trust, and potential regulatory compliance violations if personal or sensitive data is leaked. The vulnerability requires some level of privilege ("update world" permission) and knowledge of internal identifiers, which limits broad exploitation but increases risk from malicious insiders or compromised accounts with elevated permissions. The integrity and availability of the system are not directly impacted, but the confidentiality breach alone is significant. Given the network attack vector and ease of exploitation for privileged users, organizations worldwide using Venueless could face targeted data exfiltration attempts, especially in environments with multiple worlds hosted on the same server.

To mitigate CVE-2026-4982, organizations should first apply any available patches or updates from pretix once released. In the absence of patches, immediate steps include restricting the "update world" permission to only highly trusted users and regularly auditing permission assignments to minimize the number of users with this capability. Implement strict monitoring and logging of reporting feature usage and access to chat channels to detect anomalous behavior indicative of data exfiltration attempts. Network segmentation or isolation of different worlds on separate servers can reduce cross-world data leakage risk. Additionally, obfuscating or securely managing internal channel UUIDs to prevent unauthorized disclosure can further limit exploitability. Organizations should also educate administrators about the risk and enforce strong authentication and session management to prevent account compromise. Finally, consider implementing additional application-layer controls or web application firewalls (WAFs) to detect and block suspicious input patterns targeting the reporting feature.