CVE-2026-103439 describes a basic Cross-Site Scripting (XSS) vulnerability in the MediaWiki Wikbase extension maintained by The Wikimedia Foundation. The vulnerability arises from improper neutralization of script-related HTML tags, enabling injection of malicious scripts into web pages. Affected versions explicitly include 1.43, 1.45, and 1.46. The CVSS 4.0 base score is 0.3, indicating low severity, with attack vector local, high attack complexity, and requiring privileges and user interaction. No known exploits are reported in the wild. No patch or remediation details are provided in the source data.

The vulnerability allows injection of script content into web pages rendered by the MediaWiki Wikbase extension, potentially leading to Cross-Site Scripting attacks. Given the low CVSS score and the requirement for local access, privileges, and user interaction, the impact is limited. There are no known active exploits.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or patch information is provided, users should monitor the Wikimedia Foundation advisories for updates. Until a fix is available, cautious handling of user input and restricting access to trusted users may reduce risk.