CVE-2026-48991
XianYuLauncher: Legacy Microsoft account OAuth sign-in flow lacks PKCE and state validation
CVSS Score
5.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-287 |
| Vendor | xianyulauncher |
| Product | xianyulauncher |
| Published | Jun 17, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Affected Versions
XianYuLauncher / XianYuLauncher
< 1.5.5