CVE-2021-23017 Memory corruption in Nginx Web Server, Nginx Plus
An attacker forging DNS UDP packets can trigger a 1-byte memory overwrite in Nginx resolver, causing worker crashes or potential code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-23017?
CVE-2021-23017 is a high-severity memory corruption vulnerability in Fedoraproject Fedora, published on 1 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-193
Which versions are affected by CVE-2021-23017?
2 open source packages ship an affected version, including nginx and nginx-gateway. It affects 13 products.
| Package | Affected | Fixed in |
|---|---|---|
nginx Bitnami | From 0.6.18 | 1.20.1 |
nginx-gateway Bitnami | From 0.6.18 | 1.20.1 |
Linux distribution packages (38)
nginx AlmaLinux:8 | All versions | 1:1.16.1-2.module_el8.4.0+2470+68135136.1.alma |
nginx AlmaLinux:8 | All versions | 1:1.16.1-2.module_el8.5.0+35+6a1225c3.1.alma |
nginx AlmaLinux:8 | All versions | 1:1.18.0-3.module_el8.4.0+2472+f736ed63.1.alma |
nginx AlmaLinux:8 | All versions | 1:1.18.0-3.module_el8.5.0+36+48437aab.1.alma |
nginx AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.5.0+2611+ab304644.alma |
nginx AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.6.0+2782+a022aca3.alma |
nginx-all-modules AlmaLinux:8 | All versions | 1:1.16.1-2.module_el8.4.0+2470+68135136.1.alma |
nginx-all-modules AlmaLinux:8 | All versions | 1:1.18.0-3.module_el8.4.0+2472+f736ed63.1.alma |
nginx-all-modules AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.5.0+2611+ab304644.alma |
nginx-all-modules AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.6.0+2782+a022aca3.alma |
nginx-filesystem AlmaLinux:8 | All versions | 1:1.16.1-2.module_el8.4.0+2470+68135136.1.alma |
nginx-filesystem AlmaLinux:8 | All versions | 1:1.18.0-3.module_el8.4.0+2472+f736ed63.1.alma |
nginx-filesystem AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.5.0+2611+ab304644.alma |
nginx-filesystem AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.6.0+2782+a022aca3.alma |
nginx-mod-http-image-filter AlmaLinux:8 | All versions | 1:1.16.1-2.module_el8.4.0+2470+68135136.1.alma |
nginx-mod-http-image-filter AlmaLinux:8 | All versions | 1:1.16.1-2.module_el8.5.0+35+6a1225c3.1.alma |
nginx-mod-http-image-filter AlmaLinux:8 | All versions | 1:1.18.0-3.module_el8.4.0+2472+f736ed63.1.alma |
nginx-mod-http-image-filter AlmaLinux:8 | All versions | 1:1.18.0-3.module_el8.5.0+36+48437aab.1.alma |
nginx-mod-http-image-filter AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.5.0+2611+ab304644.alma |
nginx-mod-http-image-filter AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.6.0+2782+a022aca3.alma |
nginx-mod-http-perl AlmaLinux:8 | All versions | 1:1.16.1-2.module_el8.4.0+2470+68135136.1.alma |
nginx-mod-http-perl AlmaLinux:8 | All versions | 1:1.16.1-2.module_el8.5.0+35+6a1225c3.1.alma |
nginx-mod-http-perl AlmaLinux:8 | All versions | 1:1.18.0-3.module_el8.4.0+2472+f736ed63.1.alma |
nginx-mod-http-perl AlmaLinux:8 | All versions | 1:1.18.0-3.module_el8.5.0+36+48437aab.1.alma |
nginx-mod-http-perl AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.5.0+2611+ab304644.alma |
nginx-mod-http-perl AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.6.0+2782+a022aca3.alma |
nginx-mod-http-xslt-filter AlmaLinux:8 | All versions | 1:1.16.1-2.module_el8.4.0+2470+68135136.1.alma |
nginx-mod-http-xslt-filter AlmaLinux:8 | All versions | 1:1.16.1-2.module_el8.5.0+35+6a1225c3.1.alma |
nginx-mod-http-xslt-filter AlmaLinux:8 | All versions | 1:1.18.0-3.module_el8.4.0+2472+f736ed63.1.alma |
nginx-mod-http-xslt-filter AlmaLinux:8 | All versions | 1:1.18.0-3.module_el8.5.0+36+48437aab.1.alma |
nginx-mod-http-xslt-filter AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.5.0+2611+ab304644.alma |
nginx-mod-http-xslt-filter AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.6.0+2782+a022aca3.alma |
nginx-mod-mail AlmaLinux:8 | All versions | 1:1.16.1-2.module_el8.4.0+2470+68135136.1.alma |
nginx-mod-mail AlmaLinux:8 | All versions | 1:1.16.1-2.module_el8.5.0+35+6a1225c3.1.alma |
nginx-mod-mail AlmaLinux:8 | All versions | 1:1.18.0-3.module_el8.4.0+2472+f736ed63.1.alma |
nginx-mod-mail AlmaLinux:8 | All versions | 1:1.18.0-3.module_el8.5.0+36+48437aab.1.alma |
nginx-mod-mail AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.5.0+2611+ab304644.alma |
nginx-mod-mail AlmaLinux:8 | All versions | 1:1.20.1-1.module_el8.6.0+2782+a022aca3.alma |
Products include F5 Nginx, Fedoraproject Fedora, Netapp Ontap Select Deploy Administration Utility, Openresty Openresty, Oracle Blockchain Platform, Oracle Communications Control Plane Monitor and 7 more.
How do I fix CVE-2021-23017?
Upgrade nginx to 1.20.1 or later.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2021-23017 being exploited?
There is no known exploitation of CVE-2021-23017 in the wild and no public exploit code.
Public exploit code: 1 Exploit-DB entry and 9 proofs of concept on GitHub.
Other vulnerabilities in Fedoraproject Fedora
Sources
Also known as ALPINE-CVE-2021-23017, ALSA-2021:2259, ALSA-2021:2290, ALSA-2022:0323, BIT-nginx-2021-23017, BIT-nginx-gateway-2021-23017 and 33 more.