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Medium 5.5Published Jun 17, 2026

CVE-2026-48991XianYuLauncher: Legacy Microsoft account OAuth sign-in flow lacks PKCE and state validation

Updated under an hour ago ()

Does this affect you?

It affects XianYuLauncher. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
5.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Weakness (CWE)
CWE-287
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Deferred
Record last updated
Jun 18, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
XianYuLauncher XianYuLauncher
xianyulauncher:xianyulauncher (from the name)
before 1.5.5
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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