mod_auth_openidc vulnerable to denial-of-service (DoS)


mod_auth_openidc provided by ZmartZone is an OpenID Connect's Relying Party module for Apache HTTP Server. This module contains a denial-of-service (DoS) vulnerability (CWE-400).

Tatsuhiko Yasumatsu reported this vulnerability to IPA.
JPCERT/CC coordinated with the developer under Information Security Early Warning Partnership.
CVSS Severity (What is CVSS?)

CVSS V3 Severity:
Base Metrics 7.5 (High) [IPA Score]
  • Attack Vector: Network
  • Attack Complexity: Low
  • Privileges Required: None
  • User Interaction: None
  • Scope: Unchanged
  • Confidentiality Impact: None
  • Integrity Impact: None
  • Availability Impact: High
CVSS V2 Severity:
Base Metrics 5.0 (Medium) [IPA Score]
  • Access Vector: Network
  • Access Complexity: Low
  • Authentication: None
  • Confidentiality Impact: None
  • Integrity Impact: None
  • Availability Impact: Partial
Affected Products

ZmartZone IAM
  • mod_auth_openidc 2.4.0 to 2.4.7


A remote attacker may cause a denial-of-service (DoS) condition.

[Update the software]
Update to the latest version according to the information provided by the developer.
Vendor Information

ZmartZone IAM
CWE (What is CWE?)

  1. No Mapping(CWE-Other) [IPA Evaluation]
CVE (What is CVE?)

  1. CVE-2021-20718

  1. JVN : JVN#49704918
  2. National Vulnerability Database (NVD) : CVE-2021-20718
Revision History

  • [2021/05/14]
      Web page was published