{"id":"CVE-2021-31404","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-31404","generatedAt":"2026-10-27T22:29:06.075Z","title":"Non-constant-time comparison of CSRF tokens in UIDL request handler in com.vaadin:flow-server versions 1.0.0 through 1.0.13 (Vaadin 10.0.0 through 10.0.16), 1.1.0 prior to 2.0.0 (Vaadin 11 prior to 14), 2.0.0 through 2.4.6 (Vaadin 14.0.0 through…","description":"Non-constant-time comparison of CSRF tokens in UIDL request handler in com.vaadin:flow-server versions 1.0.0 through 1.0.13 (Vaadin 10.0.0 through 10.0.16), 1.1.0 prior to 2.0.0 (Vaadin 11 prior to 14), 2.0.0 through 2.4.6 (Vaadin 14.0.0 through 14.4.6), 3.0.0 prior to 5.0.0 (Vaadin 15 prior to 18), and 5.0.0 through 5.0.2 (Vaadin 18.0.0 through 18.0.5) allows attacker to guess a security token via timing attack.","published":"2021-04-23T16:15:09.000Z","lastModified":"2026-06-17T03:51:43.000Z","status":"Modified","sourceIdentifier":"security@vaadin.com","cvss":{"version":"3.1","score":2.5,"severity":"LOW","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N"},"cwe":["CWE-208","CWE-203"],"affected":["vaadin/flow","vaadin/vaadin"],"epss":{"score":0.0021,"percentile":0.11154,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.21%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/vaadin/flow/pull/9875","tags":["Patch","Third Party Advisory"],"source":"security@vaadin.com"},{"url":"https://vaadin.com/security/cve-2021-31404","tags":["Vendor Advisory"],"source":"security@vaadin.com"},{"url":"https://github.com/vaadin/flow/pull/9875","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://vaadin.com/security/cve-2021-31404","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-31404","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}