{"id":"CVE-2021-31785","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-31785","generatedAt":"2026-10-27T22:26:09.700Z","title":"The Bluetooth Classic implementation on Actions ATS2815 and ATS2819 chipsets does not properly handle the reception of multiple LMP_host_connection_req packets, allowing attackers in radio range to trigger a denial of service (deadlock) of the device…","description":"The Bluetooth Classic implementation on Actions ATS2815 and ATS2819 chipsets does not properly handle the reception of multiple LMP_host_connection_req packets, allowing attackers in radio range to trigger a denial of service (deadlock) of the device via crafted LMP packets. Manual user intervention is required to restart the device and restore Bluetooth communication.","published":"2021-09-07T07:15:07.000Z","lastModified":"2026-06-17T03:52:14.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-667"],"affected":["actions-semi/ats2819p firmware","actions-semi/ats2815 firmware","actions-semi/ats2819 firmware","actions-semi/ats2819s firmware","actions-semi/ats2819t firmware"],"epss":{"score":0.00443,"percentile":0.38229,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.44%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://dl.packetstormsecurity.net/papers/general/braktooth.pdf","tags":["Technical Description","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://launchstudio.bluetooth.com/ListingDetails/76427","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://www.actions-semi.com/index.php?id=3581&siteId=4","tags":["Broken Link","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://dl.packetstormsecurity.net/papers/general/braktooth.pdf","tags":["Technical Description","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://launchstudio.bluetooth.com/ListingDetails/76427","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.actions-semi.com/index.php?id=3581&siteId=4","tags":["Broken Link","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-31785","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}