CVE-2026-48991: Xianyulauncher

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

XianYuLauncher is a Minecraft Java Edition launcher. In versions prior to 1.5.5, sensitive authentication artifacts could be exposed during a user-initiated login under certain local attack conditions. Affected versions relied on a fixed localhost redirect URI without PKCE or state validation. Exploitation is most likely to occur when an attacker is able to observe, intercept, or otherwise interfere with the local authentication flow on the same device. This issue has been fixed in version 1.5.5.

Affected products

• Xianyulauncher Xianyulauncher: before 1.5.5 (fixed in 1.5.5)

Published 2026-06-17. Last modified 2026-06-22.