Back
CVE-2021-33604Reflected cross-site scripting in development mode handler in Vaadin 14, 15-19
- 2.5LowCVSS base score
- 0.29%Exploitation in 30 daysEPSS · top 79% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By Vaadin
- 28 days later
· 28 days later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VaadinCNA (assigner) | 3.1 | Low2.5 | CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N |
| NVDNVD · Modified | 3.1 | Low2.5 | CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.29% · top 79% of all CVEs (14 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 2.5.
Affected products
- affected 14.0.0 – < unspecified
- affected unspecified – ≤ 14.6.1
- affected 15.0.0 – < unspecified
- affected unspecified – ≤ 19.0.8
- affected 2.0.0 – < unspecified
- affected unspecified – ≤ 2.6.1
- affected 3.0.0 – < unspecified
- affected unspecified – ≤ 6.0.9
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavencom.vaadin:vaadin-bomGHSA-c99r-67x4-whj6 (opens in a new tab)
References
References2
- https://vaadin.com/security/cve-2021-33604 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/vaadin/flow/pull/11099 (opens in a new tab)x_refsource_CONFIRMx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-1309 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-c99r-67x4-whj6 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-33604)Record last updated .