{"schemaVersion":3,"id":"CVE-2021-21280","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"Contiki-NG is an open-source, cross-platform operating system for internet of things devices. It is possible to cause an out-of-bounds write in versions of Contiki-NG prior to 4.6 when transmitting a 6LoWPAN packet with a chain of extension headers. Unfortunately, the written header is not checked to be within the available space, thereby making it possible to write outside the buffer. The problem has been patched in Contiki-NG 4.6. Users can apply the patch for this vulnerability out-of-band as a workaround.","dates":{"published":"2021-06-18T20:35:10.000Z","modified":"2024-08-03T18:09:14.966Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":9.8,"severity":"critical","version":"3.1","versionLabel":"v3.1","source":"NVD","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":8.6,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":9.8,"severity":"critical","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false},{"version":"2.0","versionLabel":"v2.0","source":"NVD","score":7.5,"severity":"high","vector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.01064,"percentile":0.6432,"severity":"low","asOf":"2026-10-21T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-21T00:00:00.000Z","baselineScore":0.01064},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.01064,"percentile":0.6432}],"last30":[{"date":"2026-09-21T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.01064,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.01064,"percentile":0.6432}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[{"id":"GITHUB_CONTIKI-NG_CONTIKI-NG","name":"Contiki Ng","source":"github","url":"https://github.com/contiki-ng/contiki-ng/issues/594","maturity":"poc","reliabilityScore":0.3,"verified":false,"type":null,"platforms":[],"requiresAuth":null,"exploitdb":null,"metasploit":null}],"exploitCount":1,"weaknesses":[{"id":"CWE-787","name":"Out-of-bounds Write","description":"The product writes data past the end, or before the beginning, of the intended buffer.","type":"weakness","status":"Draft","abstraction":"Base","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/787.html"}],"affected":[{"vendor":"contiki-ng","product":"contiki-ng","name":"contiki-ng","label":"contiki-ng","ecosystem":null,"cpePart":"o","purl":null,"purlType":null,"versions":[{"text":"< 4.6","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 4.6","eol":null,"hubHref":"/vendor/contiki-ng/contiki-ng"}],"affectedCount":1,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/contiki-ng/contiki-ng/security/advisories/GHSA-r768-hrhf-v592","label":"github.com/contiki-ng/contiki-ng/security/advisories/GHSA-r768-hrhf-v592","hostname":"github.com","tags":["X Refsource CONFIRM","Exploit","Patch","Third Party Advisory"]},{"url":"https://github.com/contiki-ng/contiki-ng/pull/1409","label":"github.com/contiki-ng/contiki-ng/pull/1409","hostname":"github.com","tags":["X Refsource MISC","Patch","Third Party Advisory"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2021-06-18T20:35:10.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2024-08-03T18:09:14.966Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":70,"level":"high","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T22:29:05.663Z","stale":false,"partial":false}}