Vulnerability in Vaadin Flow-Server

CVE-2021-33604

URL encoding error in development mode handler in com.vaadin:flow-server versions 2.0.0 through 2.6.1 (Vaadin 14.0.0 through 14.6.1), 3.0.0 through 6.0.9 (Vaadin 15.0.0 through 19.0.8) allows local user to execute arbitrary JavaScript code by opening crafted URL in browser.

EPSS: 0.003 (20.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 2.5 (Low). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-33604?
CVE-2021-33604 is a low-severity vulnerability in Vaadin Flow-Server, classified under CWE-172. CVSS score: 2.5/10. Published 2021-06-24.
How severe is CVE-2021-33604?
Low severity. CVSS v3 base score is 2.5 out of 10.
Is CVE-2021-33604 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.