CVE-2021-31403: Vaadin bom Timing Side Channel Vulnerability Vulnerability

MODERATE
Advisory Identifier: GHSA-75xc-qvxh-27f8
CVSS 4.0
CWE-203 CWE-208
Published
Advisory Summary

CVE-2021-31403 is a MODERATE (CVSS 4.0) timing side channel vulnerability vulnerability (CWE-203: Observable Discrepancy) affecting Vaadin bom libraries in the Maven ecosystem. The issue involves timing side channel vulnerability in uidl request handler in vaadin 7 and 8. Remediation is available by upgrading affected packages to version 7.7.24, 8.12.3.

CVE-2021-31403 at a Glance

CVE Identifier CVE-2021-31403
GHSA Identifier GHSA-75xc-qvxh-27f8
Severity MODERATE
CVSS v3.1 Base Score 4.0
CWE Classification CWE-203: Observable Discrepancy
Affected Product Vaadin bom
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 4.0

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N).

Attack Vector Local (AV:L)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2021-31403

To remediate this vulnerability, upgrade all affected Vaadin bom dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

com.vaadin:vaadin-bom fixed: 7.7.24
<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-bom</artifactId>
    <version>7.7.24</version>
</dependency>
com.vaadin:vaadin-bom fixed: 8.12.3
<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-bom</artifactId>
    <version>8.12.3</version>
</dependency>
com.vaadin:vaadin-server fixed: 7.7.24
<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-server</artifactId>
    <version>7.7.24</version>
</dependency>
com.vaadin:vaadin-server fixed: 8.12.3
<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-server</artifactId>
    <version>8.12.3</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

mvn dependency:tree -Dincludes=com.vaadin

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-31403, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=com.vaadin

Analyze the terminal output to locate any version of Vaadin bom in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 7.7.24), your application is affected.

Note: The mvn dependency:tree -Dincludes=com.vaadin command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-203: Observable Discrepancy, where the product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor. In Vaadin bom, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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 - https://vaadin.com/security/cve-2021-31403

CVE-2021-31403 Affected Vaadin bom Versions

4 component(s)
Fixed Versions:
7.7.248.12.3
Product / Package Ecosystem Affected Versions Fixed Version
com.vaadin:vaadin-bom
Maven
≥ 7.0.0
< 7.7.24
7.7.24
com.vaadin:vaadin-bom
Maven
≥ 8.0.0
< 8.12.3
8.12.3
com.vaadin:vaadin-server
Maven
≥ 7.0.0
< 7.7.24
7.7.24
com.vaadin:vaadin-server
Maven
≥ 8.0.0
< 8.12.3
8.12.3

References

Frequently Asked Questions

What is CVE-2021-31403?
CVE-2021-31403 is a security vulnerability in Vaadin bom involving Timing side channel vulnerability in UIDL request handler in Vaadin 7 and 8 under CWE-203: Observable Discrepancy.
Which Vaadin bom versions are affected?
Affected versions include releases prior to 7.7.24, 8.12.3 across affected packages: com.vaadin:vaadin-bom, com.vaadin:vaadin-server.
What version fixes CVE-2021-31403?
Upgrading to 7.7.24, 8.12.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is vaadin-bom affected?
Yes, com.vaadin:vaadin-bom is affected in releases prior to 7.7.24, 8.12.3. Upgrade your dependency to 7.7.24, 8.12.3 or later.
Is vaadin-server affected?
Yes, com.vaadin:vaadin-server is affected in releases prior to 7.7.24, 8.12.3. Upgrade your dependency to 7.7.24, 8.12.3 or later.
What is the CVSS score of CVE-2021-31403?
CVE-2021-31403 has a CVSS v3.1 base score of 4.0 (MODERATE) with vector string CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N.
What CWE is associated with CVE-2021-31403?
CVE-2021-31403 is classified under CWE-203: Observable Discrepancy (The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.).
How can I check Maven dependencies for CVE-2021-31403?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=com.vaadin'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-75xc-qvxh-27f8",
  "modified" : "2021-04-16T23:15:02Z",
  "published" : "2021-04-19T14:51:06Z",
  "aliases" : [ "CVE-2021-31403" ],
  "summary" : "Timing side channel vulnerability in UIDL request handler in Vaadin 7 and 8",
  "details" : "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\n\n- https://vaadin.com/security/cve-2021-31403",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "com.vaadin:vaadin-bom"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.0.0"
      }, {
        "fixed" : "7.7.24"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "com.vaadin:vaadin-bom"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0.0"
      }, {
        "fixed" : "8.12.3"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "com.vaadin:vaadin-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.0.0"
      }, {
        "fixed" : "7.7.24"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "com.vaadin:vaadin-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0.0"
      }, {
        "fixed" : "8.12.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vaadin/framework/security/advisories/GHSA-75xc-qvxh-27f8"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-31403"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vaadin/framework/pull/12188"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vaadin/framework/pull/12190"
  }, {
    "type" : "WEB",
    "url" : "https://vaadin.com/security/cve-2021-31403"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-203", "CWE-208" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-04-16T23:15:02Z",
    "nvd_published_at" : "2021-04-23T16:15:00Z"
  }
}