CVE-2021-31408

Authentication.logout() helper in com.vaadin:flow-client versions 5.0.0 prior to 6.0.0 (Vaadin 18), and 6.0.0 through 6.0.4 (Vaadin 19.0.0 through 19.0.3) uses incorrect HTTP method, which, in combination with Spring Security CSRF protection, allows local attackers to access Fusion endpoints after the user attempted to log out.

CVSS 6.3 · Medium

External lookup

Potential internet exposure

Potential exposure only — not proof of vulnerability.Shodan results indicate potentially internet-exposed products, not confirmed vulnerable systems. They do not confirm that any returned system is vulnerable to CVE-2021-31408.

Product-level CPE searches intentionally omit version fields and NVD version-range or configuration certainty. Verify the exact product version and configuration independently.

Sign-in required. Shodan requires you to sign in to run these filter searches.

Product CPE queries

Derived from this CVE's existing NVD CPE 2.3 records; the application, operating-system, or hardware part is retained.

cpe:2.3:a:vaadin:flowSearch this product on Shodan
cpe:2.3:a:vaadin:vaadinSearch this product on Shodan

Exact CVE query

Eligible paid Shodan plan required

Shodan's exact vuln: filter is separate from the product searches above and requires an eligible paid Shodan plan.

vuln:CVE-2021-31408Search this CVE on Shodan

These are outbound search links only. cvebuzz makes no Shodan API call, uses no Shodan API key, and does not display live result counts.

Metadata

Canonical fields

NVD status

Unavailable

Published

Apr 23, 2021

Modified

Jun 17, 2026

Official record

Authoritative NVD record

CVSS vector

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

CWE IDs

Vendor classifications

How this vector reads

CVSS 3.1 base metrics decoded below. This explanation does not recalculate or change the NVD score.

Attack Vector (AV): Local. The attacker needs local access to the vulnerable system.
Attack Complexity (AC): High. Successful exploitation depends on conditions outside the attacker's control.
Privileges Required (PR): None. The attacker needs no privileges on the vulnerable system.
User Interaction (UI): Required. Another user must take an action for exploitation to succeed.
Scope (S): Unchanged. Impacts remain within the vulnerable security authority.
Confidentiality Impact (C): High. There is a total or serious impact to this security property.
Integrity Impact (I): High. There is a total or serious impact to this security property.
Availability Impact (A): None. There is no direct impact to this security property.

Signals

Exploitation indicators

0 stored signals · no KEV · 0 OTX pulses