Critical Arbitrary Code Execution Vulnerability in nginx
Summary
RLSA-2026:19159: Critical: nginx security update. Affects nginx versions < 2:1.26.3-6.el10_2.3. Fixed in 2:1.26.3-6.el10_2.3. How to fix ↓
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Background
nginx is a high-performance web and proxy server designed to handle a large number of concurrent connections efficiently. It is widely used for serving static content, load balancing, and as a reverse proxy. The recent vulnerability identified as CVE-2026-42945 poses a significant risk to systems running nginx, potentially allowing attackers to execute arbitrary code.
Vulnerability Detail
The vulnerability, CVE-2026-42945, allows an attacker to execute arbitrary code on the server running nginx. This issue arises from improper handling of certain requests, which can be exploited to gain unauthorized access and control over the server. The ramifications of this vulnerability are severe, as it can lead to data breaches, service disruptions, and unauthorized access to sensitive information.
How To Fix
Minimum fixed version
2:1.26.3-6.el10_2.3
This is the first release that contains the fix.
sudo dnf update nginxTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If you are unable to update nginx immediately, consider implementing strict access controls and monitoring for unusual activity on your server. Additionally, you can temporarily disable certain features that may be exploited until a patch is applied.
Conclusion
The nginx vulnerability CVE-2026-42945 presents a critical risk that requires immediate attention. Users are urged to update their installations to the latest patched version to mitigate potential threats. Regular monitoring and adherence to security best practices are essential to safeguard against such vulnerabilities.
See every vulnerability recorded for nginx →
FAQ
CVE-2026-42945 is a critical vulnerability in nginx that allows for arbitrary code execution, posing significant security risks.
You can check your nginx version by running 'nginx -v' in your terminal. If it is below 2:1.26.3-6.el10_2.3, it is vulnerable.
The vulnerability can lead to unauthorized access, data breaches, and control over the server, potentially compromising sensitive information.
Yes, you can use Vulert, which monitors open-source vulnerabilities in your software using just a manifest file. You can check your application against this vulnerability using the Vulert playground.
The CVSS score for CVE-2026-42945 is 8.1, indicating a high severity level.
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