XSS in Litespeed Technologies Openlitespeed

CVE-2021-47855

Openlitespeed 1.7.9 contains a stored cross-site scripting vulnerability in the dashboard's Notes parameter that allows administrators to inject malicious scripts. Attackers can craft a payload in the Notes field during listener configuration that will execute when an administrator clicks on the Default Icon.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (18.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 18.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2021-47855: held from 0.002 to 0.003.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-47855?
CVE-2021-47855 is a high-severity vulnerability in Litespeed Technologies Openlitespeed, classified under Cross-site Scripting. CVSS score: 7.2/10. Published 2026-01-21.
How severe is CVE-2021-47855?
High severity. CVSS v3 base score is 7.2 out of 10.