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CVE-2021-33604

13
FAUCET Score

CVE-2021-33604 is a URL encoding error affecting Vaadin Flow Server versions 2.0.0 through 2.6.1 (Vaadin 14.0.0-14.6.1) and 3.0.0 through 6.0.9 (Vaadin 15.0.0-19.0.8). This vulnerability allows a local user to execute arbitrary JavaScript by opening a specially crafted URL in their browser. It is rated with a low CVSS score of 2.5, indicating a low attack complexity and requiring user interaction, with a limited impact on confidentiality. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 2.0.0, <= 2.6.1CPE matchmatch criteria
cpe:2.3:a:vaadin:flow-server:*:*:*:*:*:*:*:*
>= 3.0.0, <= 5.0.0CPE matchmatch criteria
cpe:2.3:a:vaadin:flow-server:*:*:*:*:*:*:*:*
>= 6.0.0, <= 6.0.9CPE matchmatch criteria
cpe:2.3:a:vaadin:flow-server:*:*:*:*:*:*:*:*
>= 14.0.0, <= 14.6.1CPE matchmatch criteria
cpe:2.3:a:vaadin:vaadin:*:*:*:*:*:*:*:*
>= 15.0.0, <= 18.0.0CPE matchmatch criteria
cpe:2.3:a:vaadin:vaadin:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

2.5LOW

CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
1.0
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.29%
Probability of exploitation in next 30 days
EPSS Percentile
20.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0029 is in the 71st percentile among its peer group of 35 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

github_advisorypatch availablevia nvd_reference
View patch
mavenpatch availablevia ghsa
Product: com.vaadin:vaadin-bomFixed in: 14.6.2
mavenpatch availablevia ghsa
Product: com.vaadin:vaadin-bomFixed in: 19.0.9

Vendor Advisories (1)

mavenGHSA-c99r-67x4-whj6low

Reflected cross-site scripting in development mode handler in Vaadin 14, 15-19

Jun 28, 2021

References

github.com / vaadin/flow/pull/11099
PatchThird Party Advisory
vaadin.com / security/cve-2021-33604
Vendor Advisory