{"id":"CVE-2021-38543","aliases":["EUVD-2021-24991","GHSA-h8c4-66r2-5rr2"],"status":"published","title":"TP-Link UE330 USB splitter devices through 2021-08-09, in certain specific use cases in which the...","description":"TP-Link UE330 USB splitter devices through 2021-08-09, in certain specific use cases in which the device supplies power to audio-output equipment, allow remote attackers to recover speech signals from an LED on the device, via a telescope and an electro-optical sensor, aka a \"Glowworm\" attack. We assume that the USB splitter supplies power to some speakers. The power indicator LED of the USB splitter is connected directly to the power line, as a result, the intensity of the USB splitter's power indicator LED is correlative to its power consumption. The sound played by the connected speakers affects the USB splitter's power consumption and as a result is also correlative to the light intensity of the LED. By analyzing measurements obtained from an electro-optical sensor directed at the power indicator LED of the USB splitter, we can recover the sound played by the connected speakers.","severity":{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-10","score":0.01293,"percentile":0.70531,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"published":"2021-08-11T15:26:02Z","modified":"2026-06-17T04:02:19Z","products":[{"vendor":"tp-link","product":"ue330_firmware"}],"references":[{"url":"https://www.nassiben.com/glowworm-attack","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-38543"},{"url":"https://github.com/advisories/GHSA-h8c4-66r2-5rr2"}],"sources":{"cve":[{"id":"CVE-2021-38543","description":"TP-Link UE330 USB splitter devices through 2021-08-09, in certain specific use cases in which the device supplies power to audio-output equipment, allow remote attackers to recover speech signals from an LED on the device, via a telescope and an electro-optical sensor, aka a \"Glowworm\" attack. We assume that the USB splitter supplies power to some speakers. The power indicator LED of the USB splitter is connected directly to the power line, as a result, the intensity of the USB splitter's power indicator LED is correlative to its power consumption. The sound played by the connected speakers affects the USB splitter's power consumption and as a result is also correlative to the light intensity of the LED. By analyzing measurements obtained from an electro-optical sensor directed at the power indicator LED of the USB splitter, we can recover the sound played by the connected speakers.","status":"published","published":"2021-08-11T15:26:02Z","modified":"2024-08-04T01:44:23.424Z","updated_at":"2026-11-02T14:33:07.349244Z"}],"euvd":[{"id":"EUVD-2021-24991","description":"TP-Link UE330 USB splitter devices through 2021-08-09, in certain specific use cases in which the device supplies power to audio-output equipment, allow remote attackers to recover speech signals from an LED on the device, via a telescope and an electro-optical sensor, aka a \"Glowworm\" attack. We assume that the USB splitter supplies power to some speakers. The power indicator LED of the USB splitter is connected directly to the power line, as a result, the intensity of the USB splitter's power indicator LED is correlative to its power consumption. The sound played by the connected speakers affects the USB splitter's power consumption and as a result is also correlative to the light intensity of the LED. By analyzing measurements obtained from an electro-optical sensor directed at the power indicator LED of the USB splitter, we can recover the sound played by the connected speakers.","status":"published","published":"2021-08-11T15:26:02Z","modified":"2024-08-04T01:44:23Z","updated_at":"2026-11-03T03:24:24.781045Z"}],"ghsa":[{"id":"GHSA-h8c4-66r2-5rr2","title":"TP-Link UE330 USB splitter devices through 2021-08-09, in certain specific use cases in which the...","description":"TP-Link UE330 USB splitter devices through 2021-08-09, in certain specific use cases in which the device supplies power to audio-output equipment, allow remote attackers to recover speech signals from an LED on the device, via a telescope and an electro-optical sensor, aka a \"Glowworm\" attack. We assume that the USB splitter supplies power to some speakers. The power indicator LED of the USB splitter is connected directly to the power line, as a result, the intensity of the USB splitter's power indicator LED is correlative to its power consumption. The sound played by the connected speakers affects the USB splitter's power consumption and as a result is also correlative to the light intensity of the LED. By analyzing measurements obtained from an electro-optical sensor directed at the power indicator LED of the USB splitter, we can recover the sound played by the connected speakers.","status":"published","published":"2022-05-24T19:10:42Z","modified":"2023-01-30T05:01:29Z","updated_at":"2026-11-02T14:46:25.569206Z"}],"nvd":[{"id":"CVE-2021-38543","description":"TP-Link UE330 USB splitter devices through 2021-08-09, in certain specific use cases in which the device supplies power to audio-output equipment, allow remote attackers to recover speech signals from an LED on the device, via a telescope and an electro-optical sensor, aka a \"Glowworm\" attack. We assume that the USB splitter supplies power to some speakers. The power indicator LED of the USB splitter is connected directly to the power line, as a result, the intensity of the USB splitter's power indicator LED is correlative to its power consumption. The sound played by the connected speakers affects the USB splitter's power consumption and as a result is also correlative to the light intensity of the LED. By analyzing measurements obtained from an electro-optical sensor directed at the power indicator LED of the USB splitter, we can recover the sound played by the connected speakers.","status":"published","published":"2021-08-11T16:15:07.21Z","modified":"2026-06-17T04:02:19.997Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:P/I:N/A:N","level":"medium","assessor":"primary"}],"updated_at":"2026-11-02T14:06:56.943671Z"}]}}