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Fencer Vulns
medium 6.3

CVE-2021-31408 json

Server session is not invalidated when logout() helper method of Authentication module is used in Vaadin 18-19

published 2021-04-22 5 y ago modified 2026-06-17 4 mo ago also GHSA-mr8h-j9cv-4m8h , EUVD-2021-0848

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 25%
public exploits
0
none known

Summary

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.

Patch / fix

  • maven com.vaadin:vaadin-bom 19.0.4
  • Vaadin Vaadin 19.0.0
  • Vaadin flow-client 6.0.0

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
NVD 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
NVD 2.0 3.3 AV:L/AC:M/Au:N/C:P/I:P/A:N
GitHub 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
maven com.vaadin:vaadin-bom
>=18.0.0, <19.0.4
19.0.4

Affected products

  • Vaadin Vaadin
  • Vaadin flow-client

Classification

Weakness
  • CWE-613 DEPRECATED: Insufficient Session Expiration
  • CWE-287 Improper Authentication

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.