Read the docs
TI-2021-05876 Aliases CVE-2021-23017GHSA-83p9-mcpm-374v

A security issue in nginx resolver was identified, which might allow an attacker who is…

Priority HIGH 66CWE-193Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Code execution
Confidentiality · integrity · availability
High · High · Low
Fix status
Partial Red Hat: 11 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-193 and the CVSS impact.

Summary

A security issue in nginx resolver was identified, which might allow an attacker who is able to forge UDP packets from the DNS server to cause 1-byte memory overwrite, resulting in worker process crash or potential other impact.

Why it matters now

EPSS 0.53461 98th percentileScored 2026-11-07
Fix Partial Red Hat: 9 advisoriesRed Hat: 11 fixed, 1 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
—Nginx Web Server, Nginx PlusNginx Web Server versions 0.6.18 thru 1.20.0 before 1.20.1, Nginx plus versions R13 thru R23 before R23 P1. Nginx plus version R24 before R24 P1—No fix listedCNA
  • Nginx Web Server, Nginx Plus Vendor— Affected Nginx Web Server versions 0.6.18 thru 1.20.0 before 1.20.1, Nginx plus versions R13 thru R23 before R23 P1. Nginx plus version R24 before R24 P1 Fixed in — No fix listed CNA

CPE configurations NVD · 25

CPEVersionsRoleVendor
cpe:2.3:a:f5:nginx:*:*:*:*:*:*:*:*0.6.18 to before 1.20.1VulnerableF5
cpe:2.3:a:openresty:openresty:*:*:*:*:*:*:*:*before 1.19.3.2Vulnerableopenresty
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*33VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*34VulnerableFedoraproject
cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:*not specified by NVDVulnerableNetApp
cpe:2.3:a:oracle:blockchain_platform:*:*:*:*:*:*:*:*before 21.1.2VulnerableOracle
cpe:2.3:a:oracle:communications_control_plane_monitor:3.4:*:*:*:*:*:*:*3.4VulnerableOracle
cpe:2.3:a:oracle:communications_control_plane_monitor:4.2:*:*:*:*:*:*:*4.2VulnerableOracle
cpe:2.3:a:oracle:communications_control_plane_monitor:4.3:*:*:*:*:*:*:*4.3VulnerableOracle
cpe:2.3:a:oracle:communications_control_plane_monitor:4.4:*:*:*:*:*:*:*4.4VulnerableOracle
  • cpe:2.3:a:f5:nginx:*:*:*:*:*:*:*:* Versions 0.6.18 to before 1.20.1 Vulnerable ·F5
  • cpe:2.3:a:openresty:openresty:*:*:*:*:*:*:*:* Versions before 1.19.3.2 Vulnerable ·openresty
  • cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
  • cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
  • cpe:2.3:a:oracle:blockchain_platform:*:*:*:*:*:*:*:* Versions before 21.1.2 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:communications_control_plane_monitor:3.4:*:*:*:*:*:*:* Versions 3.4 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:communications_control_plane_monitor:4.2:*:*:*:*:*:*:* Versions 4.2 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:communications_control_plane_monitor:4.3:*:*:*:*:*:*:* Versions 4.3 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:communications_control_plane_monitor:4.4:*:*:*:*:*:*:* Versions 4.4 Vulnerable ·Oracle
Show 15 more CPE
CPEVersionsRoleVendor
cpe:2.3:a:oracle:communications_fraud_monitor:*:*:*:*:*:*:*:*3.4 – 4.4VulnerableOracle
cpe:2.3:a:oracle:communications_operations_monitor:3.4:*:*:*:*:*:*:*3.4VulnerableOracle
cpe:2.3:a:oracle:communications_operations_monitor:4.2:*:*:*:*:*:*:*4.2VulnerableOracle
cpe:2.3:a:oracle:communications_operations_monitor:4.3:*:*:*:*:*:*:*4.3VulnerableOracle
cpe:2.3:a:oracle:communications_operations_monitor:4.4:*:*:*:*:*:*:*4.4VulnerableOracle
cpe:2.3:a:oracle:communications_session_border_controller:8.4:*:*:*:*:*:*:*8.4VulnerableOracle
cpe:2.3:a:oracle:communications_session_border_controller:9.0:*:*:*:*:*:*:*9.0VulnerableOracle
cpe:2.3:a:oracle:enterprise_communications_broker:3.3.0:*:*:*:*:*:*:*3.3.0VulnerableOracle
cpe:2.3:a:oracle:enterprise_session_border_controller:8.4:*:*:*:*:*:*:*8.4VulnerableOracle
cpe:2.3:a:oracle:enterprise_session_border_controller:9.0:*:*:*:*:*:*:*9.0VulnerableOracle
cpe:2.3:a:oracle:enterprise_telephony_fraud_monitor:3.4:*:*:*:*:*:*:*3.4VulnerableOracle
cpe:2.3:a:oracle:enterprise_telephony_fraud_monitor:4.2:*:*:*:*:*:*:*4.2VulnerableOracle
cpe:2.3:a:oracle:enterprise_telephony_fraud_monitor:4.3:*:*:*:*:*:*:*4.3VulnerableOracle
cpe:2.3:a:oracle:enterprise_telephony_fraud_monitor:4.4:*:*:*:*:*:*:*4.4VulnerableOracle
cpe:2.3:a:oracle:goldengate:*:*:*:*:*:*:*:*before 21.4.0.0.0VulnerableOracle
  • cpe:2.3:a:oracle:communications_fraud_monitor:*:*:*:*:*:*:*:* Versions 3.4 – 4.4 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:communications_operations_monitor:3.4:*:*:*:*:*:*:* Versions 3.4 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:communications_operations_monitor:4.2:*:*:*:*:*:*:* Versions 4.2 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:communications_operations_monitor:4.3:*:*:*:*:*:*:* Versions 4.3 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:communications_operations_monitor:4.4:*:*:*:*:*:*:* Versions 4.4 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:communications_session_border_controller:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:communications_session_border_controller:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:enterprise_communications_broker:3.3.0:*:*:*:*:*:*:* Versions 3.3.0 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:enterprise_session_border_controller:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:enterprise_session_border_controller:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:enterprise_telephony_fraud_monitor:3.4:*:*:*:*:*:*:* Versions 3.4 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:enterprise_telephony_fraud_monitor:4.2:*:*:*:*:*:*:* Versions 4.2 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:enterprise_telephony_fraud_monitor:4.3:*:*:*:*:*:*:* Versions 4.3 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:enterprise_telephony_fraud_monitor:4.4:*:*:*:*:*:*:* Versions 4.4 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:goldengate:*:*:*:*:*:*:*:* Versions before 21.4.0.0.0 Vulnerable ·Oracle

Remediation

Red Hat 9 advisories

  • RHSA-2022:0323 Released 2022-01-31 · Red Hat rating Important
    nginx:1.20 security update
    • Red Hat Enterprise Linux AppStream (v. 8) nginx-1:1.20.1-1.module+el8.5.0+13723+ab304644.aarch64::nginx:1.20, nginx-1:1.20.1-1.module+el8.5.0+13723+ab304644.ppc64le::nginx:1.20, nginx-1:1.20.1-1.module+el8.5.0+13723+ab304644.s390x::nginx:1.20 +24
  • RHSA-2021:4618 Released 2021-11-11 · Red Hat rating Important
    Red Hat Advanced Cluster Management 2.4 images and security updates
    • Red Hat Advanced Cluster Management for Kubernetes 2.4 for RHEL 8 rhacm2/acm-grafana-rhel8, rhacm2/acm-must-gather-rhel8, rhacm2/acm-operator-bundle +47
  • RHSA-2021:3873 Released 2021-10-14 · Red Hat rating Important
    Red Hat Advanced Cluster Management 2.2.9 security, bug, and container updates
    • Red Hat Advanced Cluster Management for Kubernetes 2.2 for RHEL 7 rhacm2/management-ingress-rhel7, rhacm2/memcached-exporter-rhel7, rhacm2/search-aggregator-rhel7 +1
    • Red Hat Advanced Cluster Management for Kubernetes 2.2 for RHEL 8 rhacm2/acm-must-gather-rhel8, rhacm2/acm-operator-bundle, rhacm2/acmesolver-rhel8 +47
Show 6 more Red Hat advisories
  • RHSA-2021:3851 Released 2021-10-14 · Red Hat rating Important
    Red Hat 3scale API Management 2.11.0 Release - Container Images
    • Red Hat 3Scale AMP 2.11 3scale-amp2/3scale-rhel7-operator, 3scale-amp2/3scale-rhel7-operator-metadata, 3scale-amp2/apicast-gateway-rhel8 +7
  • RHSA-2021:3653 Released 2021-09-23 · Red Hat rating Important
    Red Hat Advanced Cluster Management 2.1.11 security fix and container updates
    • Red Hat Advanced Cluster Management for Kubernetes 2.1 for RHEL 8 rhacm2/acm-must-gather-rhel8
  • RHSA-2021:2290 Released 2021-06-08 · Red Hat rating Important
    nginx:1.16 security update
    • Red Hat Enterprise Linux AppStream (v. 8) nginx-1:1.16.1-2.module+el8.4.0+11155+68135136.1.aarch64::nginx:1.16, nginx-1:1.16.1-2.module+el8.4.0+11155+68135136.1.ppc64le::nginx:1.16, nginx-1:1.16.1-2.module+el8.4.0+11155+68135136.1.s390x::nginx:1.16 +24
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) nginx-1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1.aarch64::nginx:1.16, nginx-1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1.ppc64le::nginx:1.16, nginx-1:1.16.1-1.module+el8.1.0+11153+6c3a40a9.1.s390x::nginx:1.16 +24
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) nginx-1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1.aarch64::nginx:1.16, nginx-1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1.ppc64le::nginx:1.16, nginx-1:1.16.1-1.module+el8.2.0+11154+636e4c3b.1.s390x::nginx:1.16 +24
  • RHSA-2021:2278 Released 2021-06-07 · Red Hat rating Important
    rh-nginx116-nginx security update
    • Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) rh-nginx116-nginx-1:1.16.1-6.el7, rh-nginx116-nginx-mod-http-image-filter-1:1.16.1-6.el7, rh-nginx116-nginx-mod-http-perl-1:1.16.1-6.el7 +3
    • Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.7) rh-nginx116-nginx-1:1.16.1-6.el7, rh-nginx116-nginx-mod-http-image-filter-1:1.16.1-6.el7, rh-nginx116-nginx-mod-http-perl-1:1.16.1-6.el7 +3
    • Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) rh-nginx116-nginx-1:1.16.1-6.el7, rh-nginx116-nginx-mod-http-image-filter-1:1.16.1-6.el7, rh-nginx116-nginx-mod-http-perl-1:1.16.1-6.el7 +3
  • RHSA-2021:2259 Released 2021-06-07 · Red Hat rating Important
    nginx:1.18 security update
    • Red Hat Enterprise Linux AppStream (v. 8) nginx-1:1.18.0-3.module+el8.4.0+11152+f736ed63.1.aarch64::nginx:1.18, nginx-1:1.18.0-3.module+el8.4.0+11152+f736ed63.1.ppc64le::nginx:1.18, nginx-1:1.18.0-3.module+el8.4.0+11152+f736ed63.1.s390x::nginx:1.18 +24
  • RHSA-2021:2258 Released 2021-06-07 · Red Hat rating Important
    rh-nginx118-nginx security update
    • Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) rh-nginx118-nginx-1:1.18.0-3.el7, rh-nginx118-nginx-mod-http-image-filter-1:1.18.0-3.el7, rh-nginx118-nginx-mod-http-perl-1:1.18.0-3.el7 +3
    • Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.7) rh-nginx118-nginx-1:1.18.0-3.el7, rh-nginx118-nginx-mod-http-image-filter-1:1.18.0-3.el7, rh-nginx118-nginx-mod-http-perl-1:1.18.0-3.el7 +3
    • Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) rh-nginx118-nginx-1:1.18.0-3.el7, rh-nginx118-nginx-mod-http-image-filter-1:1.18.0-3.el7, rh-nginx118-nginx-mod-http-perl-1:1.18.0-3.el7 +3

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 8AffectedNo fix planned: Will not fix
Red Hat 3Scale AMP 2.11Fixed RHSA-2021:3851
Red Hat Advanced Cluster Management for Kubernetes 2.1 for RHEL 8Fixed RHSA-2021:3653
Red Hat Ansible Tower 3.8 for RHEL 7Fixed—
Red Hat Automation Hub 4.2 for RHEL 7Fixed—
Red Hat Automation Hub 4.2 for RHEL 8Fixed—
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2021:2259, RHSA-2021:2290, RHSA-2022:0323
Red Hat Enterprise Linux AppStream EUS (v. 8.1)Fixed RHSA-2021:2290
Red Hat Enterprise Linux AppStream EUS (v. 8.2)Fixed RHSA-2021:2290
Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2021:2258, RHSA-2021:2278
Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.7)Fixed RHSA-2021:2258, RHSA-2021:2278
Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2021:2258, RHSA-2021:2278
Not affected: 1 product
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-23017
  2. 2026-10-03 Alias added: GHSA-83p9-mcpm-374v

References

Patch 4

Advisory 4

Other 6

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences