LOW
CVE-2021-33604
CWE-172Published: June 24, 2021· Updated: Jun 17, 2026
2.5
CVSS v3.1
Official 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.
Technical Analysis
CVE-2021-33604 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorLocal
Attack ComplexityHigh
Privileges Req.None
User InteractionRequired
ScopeUnchanged
Impact
ConfidentialityLow
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
Affected Vendors & Products
vaadin2 product(s)
flow-servervaadin
Source: NVD CPE · 2 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.
Official Patches & Advisories
All References (4)
→
https://github.com/vaadin/flow/pull/11099Patch · Third Party Advisory
→
https://vaadin.com/security/cve-2021-33604Vendor Advisory
→
https://github.com/vaadin/flow/pull/11099Patch · Third Party Advisory
→
https://vaadin.com/security/cve-2021-33604Vendor Advisory
Quick Facts
CVE IDCVE-2021-33604
CVSS Score2.5 / 10
SeverityLOW
WeaknessCWE-172
CISA KEVNo
Affected1 vendor(s)
PublishedJun 24, 2021
Related CVEs (CWE-172)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-33604 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.