{"answers":{"affected":"2 open source packages ship an affected version, including org.geysermc:connector. It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-39177 in the wild and no public exploit code.","fix":"Upgrade org.geysermc:connector to 1.4.2-SNAPSHOT or later.","what":"CVE-2021-39177 is a high-severity authentication bypass vulnerability in GeyserMC Geyser, published on 30 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-39177 and fix it if it is affected.\n\nWhat it is: CVE-2021-39177 is a high-severity authentication bypass vulnerability in GeyserMC Geyser, published on 30 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-39177 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- org.geysermc:connector (Maven): affected all versions; fixed in 1.4.2-SNAPSHOT\n- org.geysermc:connector (Maven): affected all versions; fixed in 1.4.2-SNAPSHOT\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-39177/ (Markdown: https://insights.sbomify.com/CVE-2021-39177/index.md)","id":"CVE-2021-39177","markdown":"https://insights.sbomify.com/CVE-2021-39177/index.md","name":"CVE-2021-39177","record":{"aliases":["GHSA-h77f-xxx7-4858"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["account_takeover","privilege_escalation"],"network_reachable":"yes","non_default_config":false,"product_category":"Minecraft bridge server","requires_auth":"none","summary":"Attackers can impersonate any user by forging JWT tokens in login packets, allowing unauthorized access to the Minecraft bridge server.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"geyser","vendor":"geysermc"}],"cvss":{"score":7.4,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-287","name":"Improper Authentication"}],"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.","ecosystems":["Maven"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"User impersonation due to incorrect handling of the login JWT","id":"CVE-2021-39177","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Maven","product":null,"products":[],"type":"auth_bypass","year":"2021"},"n_packages":2,"n_references":3,"next":{"headline":"XSS in Image Optimization API for Next.js versions between 10.0.0 and 11.1.0","id":"CVE-2021-39178"},"packages":[{"ecosystem":"Maven","fixed":["1.4.2-SNAPSHOT"],"introduced":["0"],"last_affected":[],"package":"org.geysermc:connector","purl":null,"source":"GHSA-h77f-xxx7-4858"},{"ecosystem":"Maven","fixed":["1.4.2-SNAPSHOT"],"introduced":["0"],"last_affected":[],"package":"org.geysermc:connector","purl":"pkg:maven/org.geysermc/connector","source":"GHSA-h77f-xxx7-4858"}],"prev":{"headline":"Missing Release of Memory after Effective Lifetime in detect-character-encoding","id":"CVE-2021-39176"},"products":["Geyser"],"published":"2021-08-30","related":[{"cvss_score":2.4,"headline":"Geyser: Server-Side Request Forgery (SSRF) via Player Head Texture URL","id":"CVE-2026-42188","kev_date_added":null,"published":"2026-05-11"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-08-04","vendors":["GeyserMC"]},"summary":"Attackers can impersonate any user by forging JWT tokens in login packets, allowing unauthorized access to the Minecraft bridge server.","url":"https://insights.sbomify.com/CVE-2021-39177/"}