{"id":"CVE-2021-21281","aliases":["EUVD-2021-8652"],"status":"published","title":"Buffer overflow due to unvalidated TCP data offset","description":"Contiki-NG is an open-source, cross-platform operating system for internet of things devices. A buffer overflow vulnerability exists in Contiki-NG versions prior to 4.6. After establishing a TCP socket using the tcp-socket library, it is possible for the remote end to send a packet with a data offset that is unvalidated. The problem has been patched in Contiki-NG 4.6. Users can apply the patch for this vulnerability out-of-band as a workaround.","severity":{"version":"3.1","score":7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00918,"percentile":0.60727,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-120"],"published":"2021-06-18T20:25:10Z","modified":"2026-06-17T03:35:11Z","products":[{"vendor":"contiki-ng","product":"contiki-ng"}],"references":[{"url":"https://github.com/contiki-ng/contiki-ng/security/advisories/GHSA-mc42-fqfr-h9fp","tags":["x_refsource_CONFIRM","x_transferred","Patch","Third Party Advisory"]},{"url":"https://github.com/contiki-ng/contiki-ng/pull/1366","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory"]}],"sources":{"cve":[{"id":"CVE-2021-21281","title":"Buffer overflow due to unvalidated TCP data offset","description":"Contiki-NG is an open-source, cross-platform operating system for internet of things devices. A buffer overflow vulnerability exists in Contiki-NG versions prior to 4.6. After establishing a TCP socket using the tcp-socket library, it is possible for the remote end to send a packet with a data offset that is unvalidated. The problem has been patched in Contiki-NG 4.6. Users can apply the patch for this vulnerability out-of-band as a workaround.","status":"published","published":"2021-06-18T20:25:10Z","modified":"2024-08-03T18:09:15.191Z","cvss":[{"version":"3.1","score":7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-120"],"updated_at":"2026-11-02T14:33:00.137099Z"}],"euvd":[{"id":"EUVD-2021-8652","description":"Contiki-NG is an open-source, cross-platform operating system for internet of things devices. A buffer overflow vulnerability exists in Contiki-NG versions prior to 4.6. After establishing a TCP socket using the tcp-socket library, it is possible for the remote end to send a packet with a data offset that is unvalidated. The problem has been patched in Contiki-NG 4.6. Users can apply the patch for this vulnerability out-of-band as a workaround.","status":"published","published":"2021-06-18T20:25:10Z","modified":"2024-08-03T18:09:15Z","cvss":[{"version":"3.1","score":7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high"}],"updated_at":"2026-11-03T03:25:06.347262Z"}],"nvd":[{"id":"CVE-2021-21281","description":"Contiki-NG is an open-source, cross-platform operating system for internet of things devices. A buffer overflow vulnerability exists in Contiki-NG versions prior to 4.6. After establishing a TCP socket using the tcp-socket library, it is possible for the remote end to send a packet with a data offset that is unvalidated. The problem has been patched in Contiki-NG 4.6. Users can apply the patch for this vulnerability out-of-band as a workaround.","status":"published","published":"2021-06-18T21:15:07.85Z","modified":"2026-06-17T03:35:11.187Z","cvss":[{"version":"3.1","score":7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high","assessor":"secondary"},{"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"},{"version":"2.0","score":7.5,"vector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","level":"high","assessor":"primary"}],"cwes":["CWE-120"],"updated_at":"2026-11-02T14:06:54.892562Z"}]}}