CVE-2021-20293: Resteasy bom Cross-Site Scripting Vulnerability

HIGH
Advisory Identifier: GHSA-5h26-c766-g93v
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CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2021-20293 is a HIGH (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Resteasy bom libraries in the Maven ecosystem. The issue involves cross-site scripting. Remediation is available in the latest vendor maintenance releases.

CVE-2021-20293 at a Glance

CVE Identifier CVE-2021-20293
GHSA Identifier GHSA-5h26-c766-g93v
Severity HIGH
CVSS v3.1 Base Score 6.1
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Resteasy bom
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 6.1

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

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2021-20293

To remediate this vulnerability, upgrade all affected Resteasy 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.

org.jboss.resteasy:resteasy-bom fixed: Latest secure release 
<dependency>
    <groupId>org.jboss.resteasy</groupId>
    <artifactId>resteasy-bom</artifactId>
    <version>Latest secure release</version>
</dependency>
org.jboss.resteasy:resteasy-core fixed: Latest secure release 
<dependency>
    <groupId>org.jboss.resteasy</groupId>
    <artifactId>resteasy-core</artifactId>
    <version>Latest secure release</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=org.jboss.resteasy

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-20293, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.jboss.resteasy

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

Note: The mvn dependency:tree -Dincludes=org.jboss.resteasy 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-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Resteasy 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

A reflected Cross-Site Scripting (XSS) flaw was found in RESTEasy in all versions of RESTEasy up to 4.6.0.Final, where it did not properly handle URL encoding when calling @javax.ws.rs.PathParam without any @Produces MediaType. This flaw allows an attacker to launch a reflected XSS attack. The highest threat from this vulnerability is to data confidentiality and integrity.

CVE-2021-20293 Affected Resteasy bom Versions

2 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
org.jboss.resteasy:resteasy-bom
maven/org.jboss.resteasy/resteasy-bom
Maven
≤ 4.6.0.Final
org.jboss.resteasy:resteasy-core
maven/org.jboss.resteasy/resteasy-core
Maven
≤ 4.6.0.Final

References

NVD — CVE-2021-20293 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-20293
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=1942819
Resteasy bom Security Information SECURITY
https://security.netapp.com/advisory/ntap-20210727-0005

Frequently Asked Questions

What is CVE-2021-20293?
CVE-2021-20293 is a security vulnerability in Resteasy bom involving Cross-Site Scripting under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Resteasy bom versions are affected?
Affected versions include releases prior to current release patches across affected packages: org.jboss.resteasy:resteasy-bom, org.jboss.resteasy:resteasy-core.
What version fixes CVE-2021-20293?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is resteasy-bom affected?
Yes, org.jboss.resteasy:resteasy-bom is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
Is resteasy-core affected?
Yes, org.jboss.resteasy:resteasy-core is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2021-20293?
CVE-2021-20293 has a CVSS v3.1 base score of 6.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2021-20293?
CVE-2021-20293 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check Maven dependencies for CVE-2021-20293?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.jboss.resteasy'. 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
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5h26-c766-g93v",
  "modified" : "2021-08-31T21:05:24Z",
  "published" : "2021-06-15T15:59:27Z",
  "aliases" : [ "CVE-2021-20293" ],
  "summary" : "Cross-Site Scripting",
  "details" : "A reflected Cross-Site Scripting (XSS) flaw was found in RESTEasy in all versions of RESTEasy up to 4.6.0.Final, where it did not properly handle URL encoding when calling @javax.ws.rs.PathParam without any @Produces MediaType. This flaw allows an attacker to launch a reflected XSS attack. The highest threat from this vulnerability is to data confidentiality and integrity.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.jboss.resteasy:resteasy-bom"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "4.6.0.Final"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.jboss.resteasy:resteasy-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "4.6.0.Final"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-20293"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=1942819"
  }, {
    "type" : "WEB",
    "url" : "https://security.netapp.com/advisory/ntap-20210727-0005"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-06-14T19:27:56Z",
    "nvd_published_at" : "2021-06-10T12:15:00Z"
  }
}