{"schemaVersion":3,"id":"CVE-2021-21257","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"Contiki-NG is an open-source, cross-platform operating system for internet of things devices. The RPL-Classic and RPL-Lite implementations in the Contiki-NG operating system versions prior to 4.6 do not validate the address pointer in the RPL source routing header This makes it possible for an attacker to cause out-of-bounds writes with packets injected into the network stack. Specifically, the problem lies in the rpl_ext_header_srh_update function in the two rpl-ext-header.c modules for RPL-Classic and RPL-Lite respectively. The addr_ptr variable is calculated using an unvalidated CMPR field value from the source routing header. An out-of-bounds write can be triggered on line 151 in os/net/routing/rpl-lite/rpl-ext-header.c and line 261 in os/net/routing/rpl-classic/rpl-ext-header.c, which contain the following memcpy call with addr_ptr as destination. The problem has been patched in Contiki-NG 4.6. Users can apply a patch out-of-band as a workaround.","dates":{"published":"2021-06-18T20:55:10.000Z","modified":"2024-08-03T18:09:15.156Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":8.2,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":8.2,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","exploitability":null,"impact":null,"computed":false},{"version":"2.0","versionLabel":"v2.0","source":"NVD","score":5,"severity":"medium","vector":"AV:N/AC:L/Au:N/C:N/I:N/A:P","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.01088,"percentile":0.65002,"severity":"low","asOf":"2026-10-21T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-21T00:00:00.000Z","baselineScore":0.01088},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.01088,"percentile":0.65002}],"last30":[{"date":"2026-09-21T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.01088,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.01088,"percentile":null},{"dat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