What is CVE-2020-27388?

CVE-2020-27388 is a medium-severity vulnerability in Yourls, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2020-10-23.

How severe is CVE-2020-27388?

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

XSS in Yourls

CVE-2020-27388

Multiple Stored Cross Site Scripting (XSS) vulnerabilities exist in the YOURLS Admin Panel, Versions 1.5 - 1.7.10. An authenticated user must modify a PHP plugin with a malicious payload and upload it, resulting in multiple stored XSS issues.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2020-10-23 · last modified 2026-07-09.

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: 0.007 (51.8th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 51.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Yourls

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

af854a3a-2127-422b-91ae-364da2661108 (Product)
johnjhacking.com/blog/cve-2020-27388/ (Third Party Advisory)
github.com/YOURLS/YOURLS/pull/2761 (Third Party Advisory)

Frequently asked questions

What is CVE-2020-27388?: CVE-2020-27388 is a medium-severity vulnerability in Yourls, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2020-10-23.
How severe is CVE-2020-27388?: Medium severity. CVSS v3 base score is 5.4 out of 10.