What is CVE-2020-21101?

CVE-2020-21101 is a medium-severity vulnerability in Screenly, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-04-29.

How severe is CVE-2020-21101?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Screenly

CVE-2020-21101

Cross Site Scriptiong vulnerabilityin Screenly screenly-ose all versions, including v1.8.2 (2019-09-25-Screenly-OSE-lite.img), in the 'Add Asset' page via manipulation of a 'URL' field, which could let a remote malicious user execute arbitrary code.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-04-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.006 (47.4th percentile), scored 2026-10-03.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Screenly — versions 0.9, 0.9.1, 0.10

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/Screenly/screenly-ose/issues/1254 (Third Party Advisory)

Frequently asked questions

What is CVE-2020-21101?: CVE-2020-21101 is a medium-severity vulnerability in Screenly, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-04-29.
How severe is CVE-2020-21101?: Medium severity. CVSS v3 base score is 5.4 out of 10.