title: Timing side channel vulnerability in endpoint request handler in Vaadin 15-19
description: Non-constant-time comparison of CSRF tokens in endpoint request handler in com.vaadin:flow-server versions 3.0.0 through 5.0.3 (Vaadin 15.0.0 through 18.0.6), and com.vaadin:fusion-endpoint version 6.0.0 (Vaadin 19.0.0) allows attacker to guess a security token for Fusion endpoints via timing attack.
problem types: CWE-208 Information Exposure Through Timing Discrepancy
affected:
{
product: Vaadin
vendor: Vaadin
versions:
status: affected, version: 19.0.0
lessThan: *, status: affected, version: 15.0.0, versionType: custom
}
{
product: flow-server
vendor: Vaadin
versions:
status: affected, version: 6.0.0
lessThan: *, status: affected, version: 3.0.0, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: HIGH
attackVector: LOCAL
availabilityImpact: NONE
baseScore: 4
baseSeverity: MEDIUM
confidentialityImpact: LOW
integrityImpact: LOW
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
version: 3.1
]