CVE-2026-48991

XianYuLauncher: Legacy Microsoft account OAuth sign-in flow lacks PKCE and state validation

Published Jun 17, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Xianyulauncher
Xianyulauncher xianyulauncher
Vendors & Products Xianyulauncher
Xianyulauncher xianyulauncher
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title XianYuLauncher: Legacy Microsoft account OAuth sign-in flow lacks PKCE and state validation
Weaknesses CWE-287
References
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jun 18, 2026, 12:55 PM
Reserved
May 26, 2026, 11:26 PM
Status
Deferred
Published
Jun 17, 2026, 10:16 PM
Modified
Jun 22, 2026, 6:27 PM