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CVE-2021-33839

25
FAUCET Score

CVE-2021-33839 describes an information disclosure vulnerability in Luca through version 1.7.4 on Android. Attackers can exploit this by confusing public location QR codes with private meeting QR codes, potentially revealing sensitive COVID-19 tracking data. The vulnerability has a CVSS score of 7.5 (HIGH), indicating a network-based attack with low complexity and high confidentiality impact. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
<= 1.7.4CPE matchmatch criteria
cpe:2.3:a:luca-app:luca:*:*:*:*:*:android:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.77%
Probability of exploitation in next 30 days
EPSS Percentile
84.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0277 is in the 73rd percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

github.com / mame82/misc/blob/master/luca_traceIds.md
Third Party Advisory
luca-app.de / securityoverview/properties/objectives.html
Vendor Advisory
twitter.com / patrick_hennig/status/1387738281757061125
Third Party Advisory
youtu.be / jWyDfEB0m08
ExploitThird Party Advisory