XianYuLauncher: Legacy Microsoft account OAuth sign-in flow lacks PKCE and state validation
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-287.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| XianYuLauncher | XianYuLauncher | before 1.5.5 | 1.5.5 | Patch available | CNA |
- XianYuLauncher VendorXianYuLauncher Affected before 1.5.5 Fixed in 1.5.5 Patch available CNA
Remediation
- Fix · CNA XianYuLauncher (XianYuLauncher) Fixed in 1.5.5
Timeline
- 2026-10-02 Threatist record created from CVE-2026-48991
References
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences