What is CVE-2018-11399?

CVE-2018-11399 is a medium-severity vulnerability in Simplisafe U9k-Es1000, classified under Cleartext Transmission of Sensitive Information. CVSS score: 4.3/10. Published 2018-05-24.

How severe is CVE-2018-11399?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Simplisafe U9k-Es1000

CVE-2018-11399

SimpliSafe Original has Unencrypted Sensor Transmissions, which allows physically proximate attackers to obtain potentially sensitive information about the specific times when alarm-system events occur.

Published 2018-05-24 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.0/AV:P/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.002 (12.0th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 12th percentile — 12.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: -0.000

Affected products

Weakness classification (CWE)

CWE-319 — Cleartext Transmission of Sensitive Information

References

simplisafe.com/files/pdf/SimpliSafe_advisory_8-17-18.pdf
www.simpleorsecure.net/simplisafe-security-advisory/ (Third Party Advisory)

Frequently asked questions

What is CVE-2018-11399?: CVE-2018-11399 is a medium-severity vulnerability in Simplisafe U9k-Es1000, classified under Cleartext Transmission of Sensitive Information. CVSS score: 4.3/10. Published 2018-05-24.
How severe is CVE-2018-11399?: Medium severity. CVSS v3 base score is 4.3 out of 10.