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Fencer Vulns
high 7.5

CVE-2021-20718 json

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.

published 2021-05-20 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-8132

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.4%
EPSS 3.4% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

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.

Patch / fix

  • oracle essbase 21.3
  • libapache2-mod-auth-openidc Debian 14, Debian 13, Debian 12 2.4.4.1-2

debian advisories DEBIAN-CVE-2021-20718

  • apache2-mod_auth_openidc SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES 12 SP5 +3 more 2.4.0-3.14.1

suse advisories SUSE-SU-2021:1900-1

  • mod_auth_openidc CBL-Mariner 2.0 2.4.14.2-1

azure linux advisories AZL-7288

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-20718 updated cvss 7.5

mod_auth_openidc: DoS in oidc_util_read_post_params() in util.c

  • Red Hat Enterprise Linux 7 mod_auth_openidc Red Hat Enterprise Linux 8 cjose, mod_auth_openidc Red Hat Enterprise Linux 9 mod_auth_openidc
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.40% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • ZmartZone mod_auth_openidc

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.