CVE-2026-54617 PUBLISHED

GravitLauncher: Unauthenticated path traversal in LaunchServer FileServerHandler

Assigner: GitHub_M
Reserved: 15.06.2026 Published: 17.09.2026 Updated: 17.09.2026

GravitLauncher is an open-source Minecraft launcher based on sashok724's v3. Prior to 5.7.12, an unauthenticated remote actor can send a raw HTTP request target without a leading slash to the default LaunchServer file server on port 9274. FileServerHandler.channelRead0 in components/launchserver/src/main/java/pro/gravit/launchserver/socket/handlers/fileserver/FileServerHandler.java strips the first request-target character and resolves the remaining path against updatesDir without re-normalizing and verifying containment. This leaves parent-directory components in a no-leading-slash request and allows reading any file accessible to the LaunchServer process, including .keys/ecdsa_id, .keys/legacySalt, and LaunchServer.json. Disclosure of those files can expose signing keys, refresh-token material, and database credentials, enabling forged administrative access tokens and full authentication bypass. A normalizing L7 proxy may block the primary request form, but direct exposure and L4/TCP proxies remain affected, and netty.fileServerEnabled is enabled by default. This issue is fixed in 5.7.12.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 9.8

Product Status

Vendor GravitLauncher
Product Launcher
Versions
  • Version < 5.7.12 is affected

References

Problem Types

  • CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') CWE
  • CWE-200: Exposure of Sensitive Information to an Unauthorized Actor CWE
  • CWE-522: Insufficiently Protected Credentials CWE