What is CVE-2019-11820?

CVE-2019-11820 is a medium-severity vulnerability in Synology Calendar, classified under Insufficiently Protected Credentials. CVSS score: 5.5/10. Published 2019-05-09.

How severe is CVE-2019-11820?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Vulnerability in Synology Calendar

CVE-2019-11820

Information exposure through process environment vulnerability in Synology Calendar before 2.3.3-0620 allows local users to obtain credentials via cmdline.

Published 2019-05-09 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.003 (18.4th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 18.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Synology Calendar — versions unspecified

Weakness classification (CWE)

CWE-522 — Insufficiently Protected Credentials

References

www.synology.com/security/advisory/Synology_SA_19_21 (Vendor Advisory)

Frequently asked questions

What is CVE-2019-11820?: CVE-2019-11820 is a medium-severity vulnerability in Synology Calendar, classified under Insufficiently Protected Credentials. CVSS score: 5.5/10. Published 2019-05-09.
How severe is CVE-2019-11820?: Medium severity. CVSS v3 base score is 5.5 out of 10.