{"id":"CVE-2021-34147","aliases":["DEBIAN-CVE-2021-34147","EUVD-2021-20809","GHSA-m739-9w4c-mx4g","UBUNTU-CVE-2021-34147"],"status":"published","title":"The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1...","description":"The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 does not properly handle the reception of a malformed LMP timing accuracy response followed by multiple reconnections to the link slave, allowing attackers to exhaust device BT resources and eventually trigger a crash via multiple attempts of sending a crafted LMP timing accuracy response followed by a sudden reconnection with a random BDAddress.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.00586,"percentile":0.48286,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"published":"2021-09-07T06:26:51Z","modified":"2026-10-23T18:03:27Z","fixes":[{"ecosystem":"Debian:12","package":"bluez-firmware","fixed_in":["1.2-8"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"bluez-firmware","fixed_in":["1.2-8"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"bluez-firmware","fixed_in":["1.2-8"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"bluez-firmware","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2-8"}]}],"versions":["1.0-2","1.0-3","1.2-1","1.2-2","1.2-3","1.2-4","1.2-5","1.2-6","1.2-7","1.2-7~bpo11+1","1.2-8~bpo11+1"]},{"source":"osv","ecosystem":"Debian:13","package":"bluez-firmware","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2-8"}]}],"versions":["1.0-2","1.0-3","1.2-1","1.2-2","1.2-3","1.2-4","1.2-5","1.2-6","1.2-7","1.2-7~bpo11+1","1.2-8~bpo11+1"]},{"source":"osv","ecosystem":"Debian:14","package":"bluez-firmware","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2-8"}]}],"versions":["1.0-2","1.0-3","1.2-1","1.2-2","1.2-3","1.2-4","1.2-5","1.2-6","1.2-7","1.2-7~bpo11+1","1.2-8~bpo11+1"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"bluez-firmware","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2-7"]}],"products":[{"vendor":"cypress","product":"wireless_internet_connectivity_for_embedded_devices"}],"references":[{"url":"https://www.cypress.com/documentation/datasheets/cyw20735b1-single-chip-bluetooth-transceiver-wireless-input-devices","tags":["x_refsource_MISC","x_transferred","Vendor Advisory","advisory"]},{"url":"https://dl.packetstormsecurity.net/papers/general/braktooth.pdf","tags":["x_refsource_MISC","x_transferred","Technical Description","Third Party Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-34147"},{"url":"https://github.com/advisories/GHSA-m739-9w4c-mx4g"},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-34147","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2021-34147","tags":["report"]},{"url":"https://github.com/RPi-Distro/bluez-firmware/commit/31ad68831357d2019624004f1f0846475671088f","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-34147","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-34147","description":"The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 does not properly handle the reception of a malformed LMP timing accuracy response followed by multiple reconnections to the link slave, allowing attackers to exhaust device BT resources and eventually trigger a crash via multiple attempts of sending a crafted LMP timing accuracy response followed by a sudden reconnection with a random BDAddress.","status":"published","published":"2021-09-07T06:26:51Z","modified":"2024-08-04T00:05:52.353Z","updated_at":"2026-11-02T14:33:11.244759Z"}],"euvd":[{"id":"EUVD-2021-20809","description":"The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 does not properly handle the reception of a malformed LMP timing accuracy response followed by multiple reconnections to the link slave, allowing attackers to exhaust device BT resources and eventually trigger a crash via multiple attempts of sending a crafted LMP timing accuracy response followed by a sudden reconnection with a random BDAddress.","status":"published","published":"2021-09-07T06:26:51Z","modified":"2024-08-04T00:05:52Z","updated_at":"2026-11-03T03:24:32.880562Z"}],"ghsa":[{"id":"GHSA-m739-9w4c-mx4g","title":"The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1...","description":"The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 does not properly handle the reception of a malformed LMP timing accuracy response followed by multiple reconnections to the link slave, allowing attackers to exhaust device BT resources and eventually trigger a crash via multiple attempts of sending a crafted LMP timing accuracy response followed by a sudden reconnection with a random BDAddress.","status":"published","published":"2022-05-24T19:13:15Z","modified":"2023-01-30T05:01:55Z","updated_at":"2026-11-02T14:46:31.204916Z"}],"nvd":[{"id":"CVE-2021-34147","description":"The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 does not properly handle the reception of a malformed LMP timing accuracy response followed by multiple reconnections to the link slave, allowing attackers to exhaust device BT resources and eventually trigger a crash via multiple attempts of sending a crafted LMP timing accuracy response followed by a sudden reconnection with a random BDAddress.","status":"published","published":"2021-09-07T07:15:07.373Z","modified":"2026-06-17T03:55:30.86Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"},{"version":"2.0","score":6.1,"vector":"AV:A/AC:L/Au:N/C:N/I:N/A:C","level":"medium","assessor":"primary"}],"updated_at":"2026-11-02T14:06:58.05696Z"}],"osv":[{"id":"CVE-2021-34147","description":"The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 does not properly handle the reception of a malformed LMP timing accuracy response followed by multiple reconnections to the link slave, allowing attackers to exhaust device BT resources and eventually trigger a crash via multiple attempts of sending a crafted LMP timing accuracy response followed by a sudden reconnection with a random BDAddress.","status":"published","published":"2021-09-07T07:15:07.373Z","modified":"2026-03-14T10:59:49.599861Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:44:20.13324Z"},{"id":"DEBIAN-CVE-2021-34147","description":"The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 does not properly handle the reception of a malformed LMP timing accuracy response followed by multiple reconnections to the link slave, allowing attackers to exhaust device BT resources and eventually trigger a crash via multiple attempts of sending a crafted LMP timing accuracy response followed by a sudden reconnection with a random BDAddress.","status":"published","published":"2021-09-07T07:15:07.373Z","modified":"2026-10-23T18:03:27.207817918Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:45:35.233346Z"},{"id":"UBUNTU-CVE-2021-34147","description":"The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 does not properly handle the reception of a malformed LMP timing accuracy response followed by multiple reconnections to the link slave, allowing attackers to exhaust device BT resources and eventually trigger a crash via multiple attempts of sending a crafted LMP timing accuracy response followed by a sudden reconnection with a random BDAddress.","status":"published","published":"2021-09-07T07:15:00Z","modified":"2025-09-08T16:47:13Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:54:27.870979Z"}]}}