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CVE-2021-38545

20
FAUCET Score

CVE-2021-38545, dubbed "Glowworm," affects Raspberry Pi 3 B+, 3 B+ firmware, 4 B, and 4 B firmware devices. This vulnerability allows remote attackers to recover speech signals from an LED on the device by observing its power indicator LED with a telescope and electro-optical sensor, specifically when the Raspberry Pi powers audio-output equipment. Rated Medium severity (CVSS 5.9), it has a network attack vector and high confidentiality impact, but requires high attack complexity due to the specialized equipment and specific use case. There is no evidence of active exploitation, publicly available exploit code, or significant community discussion, suggesting a low current threat level.

Impacted Technologies

VendorProductVersion(s)CPE
<= 2021-08-09CPE matchmatch criteria
cpe:2.3:o:raspberrypi:raspberry_pi_4_model_b_firmware:*:*:*:*:*:*:*:*
<= 2021-08-09CPE matchmatch criteria
cpe:2.3:o:raspberrypi:raspberry_pi_3_model_b\+_firmware:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.9MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.29%
Probability of exploitation in next 30 days
EPSS Percentile
67.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0129 is in the 36th percentile among its peer group of 19,955 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

nassiben.com / glowworm-attack
ExploitThird Party Advisory