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Fencer Vulns
medium 5.9

CVE-2021-38547 json

Logitech Z120 and S120 speakers through 2021-08-09 allow remote attackers to recover speech signals from an LED on the device, via a telesc…

published 2021-08-11 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-24995

cvss
5.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 71%
public exploits
0
none known

Summary

Logitech Z120 and S120 speakers through 2021-08-09 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. The power indicator LED of the speakers is connected directly to the power line, as a result, the intensity of a device's power indicator LED is correlative to the power consumption. The sound played by the speakers affects their power consumption and as a result is also correlative to the light intensity of the LEDs. By analyzing measurements obtained from an electro-optical sensor directed at the power indicator LEDs of the speakers, we can recover the sound played by them.

Exploit prediction

1.35% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • nassiben.com https://www.nassiben.com/glowworm-attack referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.