Timing side channel vulnerability in endpoint request handler in Vaadin 15-19
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 software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | com.vaadin:flow-server | >= 3.0.0, < 5.0.4, >= 6.0.0, < 6.0.1 | 5.0.4, 6.0.1 |
References
- CVSS vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N- Weakness (CWE)
CWE-203, CWE-208- Platform
- Java / Kotlin (Maven)
- Package
com.vaadin:flow-server- Disclosed
- 19.04.2021
- Updated
- 11.10.2026 11:21
Sources and licenses
OSV / GitHub Advisory Database - GHSA-p7jq-v8jp-j424 - CC BY 4.0
Vulnerability history: com.vaadin:flow-server
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 13
- First → latest
- 04.2021 03.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 8
- Low 4
Disclosures per year
- 2021: 10
- 2022: 0
- 2023: 2
- 2024: 0
- 2025: 0
- 2026: 1
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Timing side channel vulnerability in endpoint request handler in Vaadin 15-19 this entry
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