CVE-2017-2646: Keycloak core Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-jc6q-27mw-p55w
Share
CVSS 7.5
CWE-835
Published
Advisory Summary

CVE-2017-2646 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')) affecting Keycloak core libraries in the Maven ecosystem. The issue involves keycloak vulnerable to infinite loop based denial of service. Remediation is available by upgrading affected packages to version 2.5.5.

CVE-2017-2646 at a Glance

CVE Identifier CVE-2017-2646
GHSA Identifier GHSA-jc6q-27mw-p55w
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
Affected Product Keycloak 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:3.0/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-2017-2646

To remediate this vulnerability, upgrade all affected Keycloak 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.

org.keycloak:keycloak-core fixed: 2.5.5 
<dependency>
    <groupId>org.keycloak</groupId>
    <artifactId>keycloak-core</artifactId>
    <version>2.5.5</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.keycloak

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2017-2646, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.keycloak

Analyze the terminal output to locate any version of Keycloak core in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.5.5), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.keycloak 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-835: Loop with Unreachable Exit Condition ('Infinite Loop'), where the product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. In Keycloak 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

When Keycloak versions prior to 2.5.5 receive a Logout request with an Extensions in the middle of the request, the SAMLSloRequestParser.parse() method ends in an infinite loop. An attacker could use this flaw to conduct denial of service attacks.

CVE-2017-2646 Affected Keycloak core Versions

1 component(s)
Fixed Versions:
2.5.5
Product / Package Ecosystem Affected Versions Fixed Version
org.keycloak:keycloak-core
maven/org.keycloak/keycloak-core
Maven
< 2.5.5
2.5.5

References

NVD — CVE-2017-2646 NVD
https://nvd.nist.gov/vuln/detail/CVE-2017-2646
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-jc6q-27mw-p55w
Keycloak core Source Repository REPOSITORY
https://github.com/keycloak/keycloak

Frequently Asked Questions

What is CVE-2017-2646?
CVE-2017-2646 is a security vulnerability in Keycloak core involving Keycloak vulnerable to infinite loop based Denial of Service under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop').
Which Keycloak core versions are affected?
Affected versions include releases prior to 2.5.5 across affected packages: org.keycloak:keycloak-core.
What version fixes CVE-2017-2646?
Upgrading to 2.5.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is keycloak-core affected?
Yes, org.keycloak:keycloak-core is affected in releases prior to 2.5.5. Upgrade your dependency to 2.5.5 or later.
What is the CVSS score of CVE-2017-2646?
CVE-2017-2646 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2017-2646?
CVE-2017-2646 is classified under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') (The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.).
How can I check Maven dependencies for CVE-2017-2646?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.keycloak'. 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-jc6q-27mw-p55w",
  "modified" : "2022-09-13T23:31:40Z",
  "published" : "2018-10-18T16:49:29Z",
  "aliases" : [ "CVE-2017-2646" ],
  "summary" : "Keycloak vulnerable to infinite loop based Denial of Service",
  "details" : "When Keycloak versions prior to 2.5.5 receive a Logout request with an Extensions in the middle of the request, the SAMLSloRequestParser.parse() method ends in an infinite loop. An attacker could use this flaw to conduct denial of service attacks.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.keycloak:keycloak-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.5.5"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2017-2646"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-jc6q-27mw-p55w"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/keycloak/keycloak"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-835" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-06-16T21:42:58Z",
    "nvd_published_at" : null
  }
}