What’s Vulnerable › Vulnerabilities

CVE-2021-31403: Timing side channel vulnerability in UIDL request handler in Vaadin 7 and 8

• Severity: low (CVSS 2.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-04-23 · updated 2026-06-17
• Weakness: CWE-208

Description

Non-constant-time comparison of CSRF tokens in UIDL request handler in com.vaadin:vaadin-server versions 7.0.0 through 7.7.23 (Vaadin 7.0.0 through 7.7.23), and 8.0.0 through 8.12.2 (Vaadin 8.0.0 through 8.12.2) allows attacker to guess a security token via timing attack

Affected products

• Vaadin: from 7.0.0 before 7.7.24; from 8.0.0 before 8.12.3 — fixed in 7.7.24, 8.12.3

How to fix

Upgrade to a fixed version: Vaadin 7.7.24, 8.12.3. Check the vendor advisory for mitigations.

References

• https://github.com/vaadin/framework/pull/12188
• https://github.com/vaadin/framework/pull/12190
• https://vaadin.com/security/cve-2021-31403
• https://github.com/vaadin/framework/pull/12188
• https://github.com/vaadin/framework/pull/12190
• https://vaadin.com/security/cve-2021-31403

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