CVE-2021-31406

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

LOW
2.5
CVSS Score
Published: April 23, 2021 at 04:05 PM UTC
Updated: June 17, 2026 at 03:51 AM UTC
3 products affected across 1 vendorVaadinFlowFlow Server

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Severity
LOW2.5
Exploit prediction
EPSS 0.2%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

3.0.0 ≤ v < 5.0.46.0.0
Affected range stops below 5.0.4, so it looks safe — our inference, not a vendor statement
v ≥ 15.0.015.0.0 ≤ v < 18.0.715.0.019.0.0
Affected range stops below 18.0.7, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

x_refsource_MISCPatchThird Party Advisory
https://github.com/vaadin/flow/pull/10157

CVSS

Attack Vector
LOCAL
Complexity
HIGH
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-208CWE-203

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