CVE-2026-116879 in Semantic MediaWiki
Summary
by MITRE • 10/27/2026
Semantic MediaWiki from 7.3.0 before 7.3.1 contains a missing authorization vulnerability in the smwtask update task that allows users with edit rights to force semantic updates on arbitrary pages. Attackers can supply a serialized subject parameter for a restricted page to trigger forced reparsing, semantic-store writes, and resource-intensive dependency work.
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Analysis
by VulDB Data Team • 10/27/2026
The vulnerability identified in Semantic MediaWiki versions prior to 7.3.1 represents a critical failure in access control mechanisms within the smwtask update task functionality. This flaw allows authenticated users who possess standard edit permissions on any page to bypass intended restrictions and force semantic updates on pages where they do not hold such privileges. The core of this issue lies in the insufficient validation of input parameters during the execution of background tasks, specifically when handling serialized subject data. By manipulating these inputs, an attacker can target restricted content that is typically protected from unauthorized modification or processing by other user groups.
From a technical perspective, the exploitation involves supplying a carefully crafted serialized object as part of the request payload to trigger the update process on arbitrary pages. This action forces the system to perform reparsing operations and write changes directly to the semantic store associated with those restricted resources. The consequence is not merely unauthorized data modification but also significant resource consumption due to dependency resolution and processing overheads inherent in Semantic MediaWiki's architecture. These systems are designed to maintain complex relationships between entities, meaning that forcing updates on unintended targets can lead to substantial computational load and potential service degradation for other users sharing the same instance.
The operational impact of this vulnerability extends beyond simple data integrity concerns. It enables a form of denial-of-service through resource exhaustion if an attacker repeatedly triggers these forced updates across multiple restricted pages or large datasets. Furthermore, it compromises the confidentiality and integrity model by allowing unauthorized entities to influence how semantic data is stored and interpreted within the wiki environment. This can lead to inconsistent states in linked resources, potentially affecting downstream applications that rely on accurate semantic metadata for decision-making processes.
This vulnerability aligns with CWE-269 Improper Privilege Management as it involves a user gaining capabilities beyond their assigned permissions level. Additionally, it relates to CWE-732 Incorrect Permission Assignment for Critical Resource because the system fails to enforce proper access controls on specific wiki pages during task execution. In terms of attack vectors and tactics, this behavior corresponds to ATT&CK technique T1059 Command and Scripting Interpreter if viewed through the lens of automated exploitation scripts used by attackers, although more directly it reflects unauthorized actions enabled by flawed authorization logic rather than direct command injection.
Mitigation strategies should prioritize immediate patching to version 7.3.1 or later where this access control flaw has been addressed. Administrators must ensure that all instances running affected versions are updated promptly to close the gap in permission validation for the smwtask update task. In environments where upgrading is not immediately feasible, implementing strict input filtering on serialized parameters and restricting direct access to internal API endpoints used by background tasks can provide temporary relief. Regular auditing of user permissions and monitoring system logs for unusual spikes in semantic store write operations may also help detect ongoing exploitation attempts before significant damage occurs.