{"id":"CVE-2021-39177","state":"PUBLISHED","title":"User impersonation due to incorrect handling of the login JWT","description":"Geyser is a bridge between Minecraft: Bedrock Edition and Minecraft: Java Edition. Versions of Geyser prior to 1.4.2-SNAPSHOT allow anyone that can connect to the server to forge a LoginPacket with manipulated JWT token allowing impersonation as any user. Version 1.4.2-SNAPSHOT contains a patch for the issue. There are no known workarounds aside from upgrading.","publishedAt":"2021-08-30T23:00:12.000Z","updatedAt":"2024-08-04T01:58:18.223Z","severity":{"score":7.4,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["GeyserMC Geyser"],"affected":[{"vendor":"GeyserMC","product":"Geyser","versions":[{"version":"<= 1.4.1-SNAPSHOT","status":"affected"}]}],"references":["https://github.com/GeyserMC/Geyser/security/advisories/GHSA-h77f-xxx7-4858","https://github.com/GeyserMC/Geyser/commit/b9541505af68ac7b7c093206ac7b1ba88957a5a6","https://updates.playhive.com/weekend-maintenance-disclosure-2kJMaY"],"weaknesses":["CWE-287"],"ingestedAt":"2026-10-29T19:48:52.666Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/39xxx/CVE-2021-39177.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2021-39177","state":"PUBLISHED","datePublished":"2021-08-30T23:00:12.000Z","dateUpdated":"2024-08-04T01:58:18.223Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2021-08-16T00:00:00.000Z"},"containers":{"cna":{"title":"User impersonation due to incorrect handling of the login JWT","descriptions":[{"lang":"en","value":"Geyser is a bridge between Minecraft: Bedrock Edition and Minecraft: Java Edition. 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