CVE-2021-3859: Undertow core Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-339q-62wm-c39w
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CVSS 7.5
CWE-668 CWE-400 CWE-214
Published
Advisory Summary

CVE-2021-3859 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-668: Exposure of Resource to Wrong Sphere) affecting Undertow core libraries in the Maven ecosystem. The issue involves undertow vulnerable to denial of service (dos) attacks. Remediation is available by upgrading affected packages to version 2.2.15.

CVE-2021-3859 at a Glance

CVE Identifier CVE-2021-3859
GHSA Identifier GHSA-339q-62wm-c39w
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-668: Exposure of Resource to Wrong Sphere
Affected Product Undertow core
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.5

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:N/S:U/C:N/I:N/A:H).

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

How to Fix CVE-2021-3859

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

io.undertow:undertow-core fixed: 2.2.15 
<dependency>
    <groupId>io.undertow</groupId>
    <artifactId>undertow-core</artifactId>
    <version>2.2.15</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=io.undertow

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-3859, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=io.undertow

Analyze the terminal output to locate any version of Undertow core in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.2.15), your application is affected.

Note: The mvn dependency:tree -Dincludes=io.undertow 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-668: Exposure of Resource to Wrong Sphere, where the product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource. In Undertow core, 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

Undertow client side invocation timeout raised when calling over HTTP2, this vulnerability can allow attacker to carry out denial of service (DoS) attacks in versions less than 2.2.15 Final.

CVE-2021-3859 Affected Undertow core Versions

1 component(s)
Fixed Versions:
2.2.15
Product / Package Ecosystem Affected Versions Fixed Version
io.undertow:undertow-core
maven/io.undertow/undertow-core
Maven
< 2.2.15
2.2.15

References

NVD — CVE-2021-3859 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-3859
Undertow core Source Repository REPOSITORY
https://github.com/undertow-io/undertow/pull/1296
Security Fix Commit FIX COMMIT
https://github.com/undertow-io/undertow/commit/db0f5be43f8e2a4b88fbedd2eb6d5a95a29ceaa8
Security Fix Commit FIX COMMIT
https://github.com/undertow-io/undertow/commit/e43f0ada3f4da6e8579e0020cec3cb1a81e487c2
Undertow core Security Information SECURITY
https://access.redhat.com/security/cve/cve-2021-3859
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2010378
Undertow core Source Repository REPOSITORY
https://github.com/undertow-io/undertow
issues.redhat.com/browse/undertow-197... WEB
https://issues.redhat.com/browse/UNDERTOW-1979
Undertow core Security Information SECURITY
https://security.netapp.com/advisory/ntap-20221201-0004

Frequently Asked Questions

What is CVE-2021-3859?
CVE-2021-3859 is a security vulnerability in Undertow core involving Undertow vulnerable to Denial of Service (DoS) attacks under CWE-668: Exposure of Resource to Wrong Sphere.
Which Undertow core versions are affected?
Affected versions include releases prior to 2.2.15 across affected packages: io.undertow:undertow-core.
What version fixes CVE-2021-3859?
Upgrading to 2.2.15 (or the latest patched release for your respective branch) resolves the vulnerability.
Is undertow-core affected?
Yes, io.undertow:undertow-core is affected in releases prior to 2.2.15. Upgrade your dependency to 2.2.15 or later.
What is the CVSS score of CVE-2021-3859?
CVE-2021-3859 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2021-3859?
CVE-2021-3859 is classified under CWE-668: Exposure of Resource to Wrong Sphere (The product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource.).
How can I check Maven dependencies for CVE-2021-3859?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=io.undertow'. 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-339q-62wm-c39w",
  "modified" : "2022-09-08T14:24:12Z",
  "published" : "2022-07-15T21:32:13Z",
  "aliases" : [ "CVE-2021-3859" ],
  "summary" : "Undertow vulnerable to Denial of Service (DoS) attacks",
  "details" : "Undertow client side invocation timeout raised when calling over HTTP2, this vulnerability can allow attacker to carry out denial of service (DoS) attacks in versions less than 2.2.15 Final.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "io.undertow:undertow-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.2.15"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-3859"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/undertow-io/undertow/pull/1296"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/undertow-io/undertow/commit/db0f5be43f8e2a4b88fbedd2eb6d5a95a29ceaa8"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/undertow-io/undertow/commit/e43f0ada3f4da6e8579e0020cec3cb1a81e487c2"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/security/cve/cve-2021-3859"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2010378"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/undertow-io/undertow"
  }, {
    "type" : "WEB",
    "url" : "https://issues.redhat.com/browse/UNDERTOW-1979"
  }, {
    "type" : "WEB",
    "url" : "https://security.netapp.com/advisory/ntap-20221201-0004"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-214", "CWE-400", "CWE-668" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-07-15T21:32:13Z",
    "nvd_published_at" : "2022-08-26T16:15:00Z"
  }
}