CVE-2021-33609

Denial of service in DataCommunicator class in Vaadin 8

4.3 MediumFix available

Missing check in DataCommunicator class in com.vaadin:vaadin-server versions 8.0.0 through 8.14.0 (Vaadin 8.0.0 through 8.14.0) allows authenticated network attacker to cause heap exhaustion by requesting too many rows of data.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: Low

Exploit likelihood

0.95%Up 0.3 points since Oct 14, 2021

What each source reports

CVE List Score used 4.3

Denial of service in DataCommunicator class in Vaadin 8

Record: CVE-2021-33609
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Weakness: CWE-400
Updated: 2026-11-02

EUVDEUVD-2021-2248 4.3

Record: EUVD-2021-2248
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Updated: 2026-11-03

GitHub AdvisoriesGHSA-qcgx-crrx-38v5 4.3

Denial of service in DataCommunicator class in Vaadin 8

Missing check in DataCommunicator class in com.vaadin:vaadin-server versions 8.0.0 through 8.14.0 (Vaadin 8.0.0 through 8.14.0) allows authenticated network attacker to cause heap exhaustion by requesting too many rows of data.

Record: GHSA-qcgx-crrx-38v5
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Weakness: CWE-20, CWE-400
Updated: 2026-11-02

NVD 4.3

Record: CVE-2021-33609
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CVSS 2.0: 4.0 MediumAV:N/AC:L/Au:S/C:N/I:N/A:P
Weakness: CWE-400, CWE-20
Updated: 2026-11-02

OSV 4.3

Record: CVE-2021-33609
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Updated: 2026-11-02

OSVGHSA-qcgx-crrx-38v5 4.3

Denial of service in DataCommunicator class in Vaadin 8

Record: GHSA-qcgx-crrx-38v5
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Weakness: CWE-20, CWE-400
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`com.vaadin:vaadin-server` Maven	8.0.6 up to 8.14.1	8.14.1
`com.vaadin:vaadin-server` Maven	8.0.6 up to 8.14.1, plus listed versions 8.0.78.1.08.1.18.1.28.1.3 Show 45 moreShow less 8.1.48.1.58.1.68.1.78.1.88.10.08.10.18.10.28.10.38.10.48.10.58.11.08.11.18.11.28.11.38.12.08.12.18.12.28.12.38.12.48.13.08.13.18.13.28.13.38.14.08.2.08.2.18.3.08.3.18.3.28.3.38.4.08.4.18.4.28.4.38.4.48.4.58.5.08.5.18.5.28.6.08.6.18.6.28.6.38.6.4	8.14.1

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases, published	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-33609 is a medium vulnerability (CVSS 4.3) in Vaadin, published October 13, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.95%, the 61st percentile. Fixed in com.vaadin:vaadin-server 8.14.1.

References

This page doesn't list everything

Left out here: 16 versions. The JSON record has them.