CVE-2021-20718

CVE-2021-20718 affecting package mod_auth_openidc for versions less than 2.4.14.2-1

7.5 HighFix available

mod_auth_openidc 2.4.0 to 2.4.7 allows a remote attacker to cause a denial-of-service (DoS) condition via unspecified vectors.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

3.40%Up 2.3 points since May 20, 2021

What each source reports

NVD Score used 7.5

mod_auth_openidc 2.4.0 to 2.4.7 allows a remote attacker to cause a denial-of-service (DoS) condition via unspecified vectors.

Record: CVE-2021-20718
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0: 5.0 MediumAV:N/AC:L/Au:N/C:N/I:N/A:P
Weakness: CWE-400
Updated: 2026-11-02

CVE List No score

mod_auth_openidc 2.4.0 to 2.4.7 allows a remote attacker to cause a denial-of-service (DoS) condition via unspecified vectors.

Record: CVE-2021-20718
Updated: 2026-11-02

EUVDEUVD-2021-8132 No score

mod_auth_openidc 2.4.0 to 2.4.7 allows a remote attacker to cause a denial-of-service (DoS) condition via unspecified vectors.

Record: EUVD-2021-8132
Updated: 2026-11-03

OSVAZL-7288 7.5

CVE-2021-20718 affecting package mod_auth_openidc for versions less than 2.4.14.2-1

mod_auth_openidc 2.4.0 to 2.4.7 allows a remote attacker to cause a denial-of-service (DoS) condition via unspecified vectors.

Record: AZL-7288
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSV 7.5

mod_auth_openidc 2.4.0 to 2.4.7 allows a remote attacker to cause a denial-of-service (DoS) condition via unspecified vectors.

Record: CVE-2021-20718
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVDEBIAN-CVE-2021-20718 7.5

mod_auth_openidc 2.4.0 to 2.4.7 allows a remote attacker to cause a denial-of-service (DoS) condition via unspecified vectors.

Record: DEBIAN-CVE-2021-20718
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVUBUNTU-CVE-2021-20718 7.5

mod_auth_openidc 2.4.0 to 2.4.7 allows a remote attacker to cause a denial-of-service (DoS) condition via unspecified vectors.

Record: UBUNTU-CVE-2021-20718
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVMGASA-2021-0280 No score

Updated apache-mod_auth_openidc package fixes a security vulnerability

mod_auth_openidc 2.4.0 to 2.4.7 allows a remote attacker to cause a denial-of- service (DoS) condition via unspecified vectors (CVE-2021-20718).

Record: MGASA-2021-0280
Updated: 2026-11-02

OSVSUSE-SU-2021:1900-1 No score

Security update for apache2-mod_auth_openidc

This update for apache2-mod_auth_openidc fixes the following issues:

CVE-2021-20718: Fixed possible remote denial-of-service (DoS) via unspecified vectors (bsc#1186291).

Record: SUSE-SU-2021:1900-1
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`mod_auth_openidc` Azure Linux:2	before 2.4.14.2-1	2.4.14.2-1
`libapache2-mod-auth-openidc` Debian:12	before 2.4.4.1-2	2.4.4.1-2
`libapache2-mod-auth-openidc` Debian:13	before 2.4.4.1-2	2.4.4.1-2
`libapache2-mod-auth-openidc` Debian:14	before 2.4.4.1-2	2.4.4.1-2
`apache-mod_auth_openidc` Mageia:8	before 2.4.2.1-1.1.mga8	2.4.2.1-1.1.mga8
`apache2-mod_auth_openidc` SUSE:OpenStack Cloud 9	before 2.4.0-3.14.1	2.4.0-3.14.1
`apache2-mod_auth_openidc` SUSE:OpenStack Cloud Crowbar 9	before 2.4.0-3.14.1	2.4.0-3.14.1
`apache2-mod_auth_openidc` SUSE:Linux Enterprise Server for SAP Applications 12 SP4	before 2.4.0-3.14.1	2.4.0-3.14.1
`apache2-mod_auth_openidc` SUSE:Linux Enterprise Server 12 SP4-LTSS	before 2.4.0-3.14.1	2.4.0-3.14.1
`apache2-mod_auth_openidc` SUSE:Linux Enterprise Server 12 SP5	before 2.4.0-3.14.1	2.4.0-3.14.1
`apache2-mod_auth_openidc` SUSE:Linux Enterprise Server for SAP Applications 12 SP5	before 2.4.0-3.14.1	2.4.0-3.14.1
`libapache2-mod-auth-openidc` Ubuntu:20.04:LTS	All versions, plus listed versions 2.3.10.2-12.4.0.4-12.4.1-1	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-20718 is a high vulnerability (CVSS 7.5) in Fedoraproject Fedora, published May 20, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 3.40%, the 88th percentile. Fixed in mod_auth_openidc 2.4.14.2-1.

References

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