CVE-2026-0817 in CampaignEvents Extension
Summary
by MITRE • 01/09/2026
Missing Authorization vulnerability in Wikimedia Foundation MediaWiki - CampaignEvents extension allows Privilege Abuse.This issue affects MediaWiki - CampaignEvents extension: 1.45, 1.44, 1.43, 1.39.
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Analysis
by VulDB Data Team • 02/10/2026
The CVE-2026-0817 vulnerability represents a critical authorization flaw within the Wikimedia Foundation MediaWiki CampaignEvents extension, exposing systems to unauthorized privilege abuse. This vulnerability specifically targets the extension versions 1.45, 1.44, 1.43, and 1.39, indicating a widespread impact across multiple stable releases of the MediaWiki platform. The issue stems from insufficient access controls that fail to properly validate user permissions before granting administrative or sensitive operational capabilities within the campaign events management system.
The technical implementation of this authorization bypass occurs when the CampaignEvents extension fails to enforce proper user role validation during critical operations. Attackers can exploit this weakness to perform actions typically restricted to administrators or authorized users, potentially gaining access to campaign data, modifying event configurations, or executing privileged operations without proper authentication. This flaw aligns with CWE-285, which categorizes improper authorization as a fundamental security weakness where systems fail to properly verify that actors have appropriate access rights to perform requested operations.
From an operational perspective, this vulnerability poses significant risks to Wikimedia Foundation projects and the broader MediaWiki ecosystem. Organizations relying on CampaignEvents for managing fundraising campaigns, user engagement initiatives, or community outreach programs face potential data compromise, unauthorized modifications, and possible service disruption. The impact extends beyond individual wiki instances to affect the entire Wikimedia infrastructure, given the widespread adoption of MediaWiki across thousands of projects and the interconnected nature of the foundation's services. Attackers exploiting this vulnerability could manipulate campaign metrics, access sensitive donor information, or disrupt ongoing community initiatives that depend on the extension's functionality.
The security implications of CVE-2026-0817 align with ATT&CK technique T1078.004, which covers legitimate credentials abuse through unauthorized access to privileged accounts. This vulnerability essentially allows attackers to bypass normal authentication mechanisms and assume elevated privileges within the CampaignEvents extension. Organizations should implement immediate mitigations including applying the latest security patches from Wikimedia Foundation, reviewing and strengthening access controls, and monitoring for unauthorized activities within campaign management systems. Additionally, implementing network segmentation and least-privilege access principles can help limit the potential impact of such authorization bypasses. The vulnerability highlights the importance of proper input validation and access control enforcement in web applications, particularly those handling sensitive community data and financial campaign information.