CVE-2026-48991

Account token disclosure via unbound OAuth callback

Published Jun 17, 2026 · Updated Jun 17, 2026

Improper authentication in Spirit Studio XianYu Launcher before 1.5.5 allows local users to expose Microsoft account tokens during login. The legacy browser sign-in flow uses a fixed localhost redirect URI and binds neither a PKCE verifier nor state value to the authorization response. Exploitation requires a user-initiated sign-in and same-device access to observe, intercept, or interfere with the loopback callback, exposing authentication artifacts without reported integrity or availability impact.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in Spirit Studio XianYu Launcher before 1.5.5 allows local users to expose Microsoft account tokens during login. The legacy browser sign-in flow uses a fixed localhost redirect URI and binds neither a PKCE verifier nor state value to the authorization response. Exploitation requires a user-initiated sign-in and same-device access to observe, intercept, or interfere with the loopback callback, exposing authentication artifacts without reported integrity or availability impact.

The record

CVE
CVE-2026-48991
Published
Jun 17, 2026
Updated
Jun 17, 2026
Vendor
Spirit Studio
Product
XianYu Launcher
Classifications
CWE-287, T1528
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.5.5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Spirit Studio · XianYu Launcherversion=< 1.5.5

Published CVSS scores

5.5GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1528Steal Application Access Token

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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