{"id":"CVE-2020-6840","aliases":["EUVD-2020-27983","GHSA-4v2f-5xhv-8ff4","UBUNTU-CVE-2020-6840"],"status":"published","title":"In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.","description":"In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.","severity":{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.01505,"percentile":0.74545,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-416"],"published":"2020-01-11T02:05:24Z","modified":"2026-10-20T10:53:29Z","affected":[{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"mruby","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.1.0+20150817+gita1731254-1","1.1.0+20150906+git1cbbb7e1-1","1.2.0+20160315+git4f20d58a-1"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"mruby","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0-1","1.3.0+20170925+git38185028-1","1.3.0+20171029+git77edafb0-1","1.4.0-1"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"mruby","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.0-1"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"mruby","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.1.2-3","3.0.0-1","3.0.0-3"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"mruby","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.2.0-1","3.2.0-2"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"mruby","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.3.0-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"mruby","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.4.0-2","3.4.0-3","4.0.0-1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"mruby","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.3.0-1","3.4.0-2"]}],"products":[{"vendor":"mruby","product":"mruby"}],"references":[{"url":"https://github.com/mruby/mruby/issues/4927","tags":["x_refsource_MISC","x_transferred","Exploit","Patch","Third Party Advisory","fix","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-6840"},{"url":"https://github.com/advisories/GHSA-4v2f-5xhv-8ff4"},{"url":"https://ubuntu.com/security/CVE-2020-6840","tags":["report"]},{"url":"https://github.com/mruby/mruby/commit/fc8fb41451b07b3fda0726ba80e88e509ad02452","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2020-6840","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2020-6840","description":"In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.","status":"published","published":"2020-01-11T02:05:24Z","modified":"2024-08-04T09:11:05.202Z","updated_at":"2026-11-02T14:35:52.592504Z"}],"euvd":[{"id":"EUVD-2020-27983","description":"In mruby 2.1.0, there is a use-after-free in hash_slice in 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mrbgems/mruby-hash-ext/src/hash-ext.c.","status":"published","published":"2020-01-11T03:15:00Z","modified":"2026-10-17T12:56:57.086926857Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:54:25.728622Z"}]}}