CVE-2026-48991 — XianYuLauncher: Legacy Microsoft account OAuth sign-in flow lacks PKCE and state validation
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 …
Published: 2026-06-17 · CVSS: 5.5 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7