GHSA-9h6g-6mxg-vvp4: com.vaadin:vaadin-bom

Timing side channel vulnerability in endpoint request handler in Vaadin 15-19

CVSS 4.0 Medium

Published by the GitHub Advisory Database at 19 Apr 2021, 14:47 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
com.vaadin:vaadin-bom	Maven	>=19.0.0, <19.0.1 \|\| >=15.0.0, <18.0.7	19.0.1, 18.0.7

Identifiers

GHSA-9h6g-6mxg-vvp4

Weakness (CWE)

CWE-208

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Vaadin versions 15 through 18 before 18.0.7 and version 19.0.0 of the Vaadin BOM are affected, because CSRF tokens in the endpoint request handler are compared in a way that is not constant-time. An attacker who can send many requests to the application may use a timing attack to guess a security token for Fusion endpoints. Upgrade to Vaadin 18.0.7 or 19.0.1.

Written 8 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
4.0	Medium	3.1	CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N	GitHub Advisory Database

CISA KEV Not listed.
EPSS No score.

Timeline

31 Oct 2026, 15:12 UTC First seen by agentprime
31 Oct 2026, 15:12 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.