RHSA-2021:2259: Important: nginx:1.18 security update
Published Jun 7, 2021
·Updated
nginx is a web and proxy server supporting HTTP and other protocols, with a focus on high concurrency, performance, and low memory usage. Security Fix(es): nginx: Off-by-one in ngx_resolver_copy() when labels are followed by a pointer to a root domain name (CVE-2021-23017) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
Affected Software
54 affected componentsFixes available
redhat/nginx<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-all-modules<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-debugsource<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-filesystem<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-image-filter<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-image-filter-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-perl<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-perl-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-xslt-filter<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-xslt-filter-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-mail<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-mail-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-stream<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-stream-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-debugsource<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-image-filter<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-image-filter-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-perl<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-perl-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-xslt-filter<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-xslt-filter-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-mail<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-mail-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-stream<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-stream-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-debugsource<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-image-filter<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-image-filter-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-perl<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-perl-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-xslt-filter<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-http-xslt-filter-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-mail<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-mail-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-stream<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx-mod-stream-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1
1.18.0-3.module+el8.4.0+11152+f736ed63.1
redhat/nginx<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
redhat/nginx-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
redhat/nginx-debugsource<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
redhat/nginx-mod-http-image-filter<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
redhat/nginx-mod-http-image-filter-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
redhat/nginx-mod-http-perl<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
redhat/nginx-mod-http-perl-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
redhat/nginx-mod-http-xslt-filter<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
redhat/nginx-mod-http-xslt-filter-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
redhat/nginx-mod-mail<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
redhat/nginx-mod-mail-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
redhat/nginx-mod-stream<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
redhat/nginx-mod-stream-debuginfo<1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
1.18.0-3.module+el8.4.0+11152+f736ed63.1.aa
Remediation
Event History
Feb 27, 2026
Advisory Published
via Red Hat·05:17 PM
Data Sourced
via Red Hat·05:17 PM
RemedyDescriptionAffected Software
Frequently Asked Questions
1
What is the severity of RHSA-2021:2259?
The severity of RHSA-2021:2259 is classified as important.
2
How do I fix RHSA-2021:2259?
To fix RHSA-2021:2259, you should update nginx to version 1.18.0-3.module+el8.4.0+11152+f736ed63.1 or newer.
3
What types of software are affected by RHSA-2021:2259?
RHSA-2021:2259 affects nginx, nginx-debuginfo, nginx-debugsource, and several modules related to nginx.
4
What vulnerabilities are addressed in RHSA-2021:2259?
RHSA-2021:2259 addresses an off-by-one vulnerability in ngx_resolver_copy() related to DNS resolution.
5
Is there a recommended action for users of nginx regarding RHSA-2021:2259?
It is recommended that users of nginx upgrade to the fixed versions immediately to mitigate potential risks.