{"id":"CVE-2020-12886","aliases":["EUVD-2020-5167","GHSA-8v45-9mw2-ffmm"],"status":"published","title":"A buffer over-read was discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is...","description":"A buffer over-read was discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse() parses the CoAP packet header starting from the message token. The length of the token in the received message is provided in the first byte parsed by the sn_coap_parser_options_parse() function. The length encoded in the message is not validated against the actual input buffer length before accessing the token. As a result, memory access outside of the intended boundary of the buffer may occur.","severity":{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-11","score":0.01352,"percentile":0.71908,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-125"],"published":"2020-06-18T18:24:51Z","modified":"2026-06-17T02:52:29Z","products":[{"vendor":"arm","product":"mbed_os"}],"references":[{"url":"https://github.com/ARMmbed/mbed-os/issues/12948","tags":["x_refsource_MISC","x_transferred","Third Party Advisory"]},{"url":"https://github.com/ARMmbed/mbed-coap/pull/116","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-12886"},{"url":"https://github.com/advisories/GHSA-8v45-9mw2-ffmm"}],"sources":{"cve":[{"id":"CVE-2020-12886","description":"A buffer over-read was discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse() parses the CoAP packet header starting from the message token. The length of the token in the received message is provided in the first byte parsed by the sn_coap_parser_options_parse() function. The length encoded in the message is not validated against the actual input buffer length before accessing the token. As a result, memory access outside of the intended boundary of the buffer may occur.","status":"published","published":"2020-06-18T18:24:51Z","modified":"2024-08-04T12:11:18.975Z","updated_at":"2026-11-02T14:35:53.236501Z"}],"euvd":[{"id":"EUVD-2020-5167","description":"A buffer over-read was discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse() parses the CoAP packet header starting from the message token. The length of the token in the received message is provided in the first byte parsed by the sn_coap_parser_options_parse() function. The length encoded in the message is not validated against the actual input buffer length before accessing the token. As a result, memory access outside of the intended boundary of the buffer may occur.","status":"published","published":"2020-06-18T18:24:51Z","modified":"2024-08-04T12:11:18Z","updated_at":"2026-11-03T03:07:38.81332Z"}],"ghsa":[{"id":"GHSA-8v45-9mw2-ffmm","title":"A buffer over-read was discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is...","description":"A buffer over-read was discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse() parses the CoAP packet header starting from the message token. The length of the token in the received message is provided in the first byte parsed by the sn_coap_parser_options_parse() function. The length encoded in the message is not validated against the actual input buffer length before accessing the token. As a result, memory access outside of the intended boundary of the buffer may occur.","status":"published","published":"2022-05-24T17:20:51Z","modified":"2023-01-29T05:03:20Z","updated_at":"2026-11-02T14:45:18.070616Z"}],"nvd":[{"id":"CVE-2020-12886","description":"A buffer over-read was discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse() parses the CoAP packet header starting from the message token. The length of the token in the received message is provided in the first byte parsed by the sn_coap_parser_options_parse() function. The length encoded in the message is not validated against the actual input buffer length before accessing the token. As a result, memory access outside of the intended boundary of the buffer may occur.","status":"published","published":"2020-06-18T19:15:11.567Z","modified":"2026-06-17T02:52:29.297Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":6.4,"vector":"AV:N/AC:L/Au:N/C:P/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-125"],"updated_at":"2026-11-02T14:06:07.249892Z"}]}}