Critical Security Vulnerability in nginx: Denial of Service and Code Execution Risks
Summary
ALSA-2026:7002: Important: nginx security update. Affects nginx versions < 2:1.20.1-24.el9_7.2.alma.1. Fixed in 2:1.20.1-24.el9_7.2.alma.1. How to fix ↓
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Background
nginx is a high-performance web and proxy server that supports HTTP and other protocols, designed for high concurrency, performance, and low memory usage. It is widely used for serving static content, load balancing, and as a reverse proxy. However, recent vulnerabilities have been identified that could potentially compromise the security and stability of systems running nginx.
Vulnerability Detail
The vulnerabilities in nginx stem from improper handling of specially crafted MP4 files and buffer overflow issues in the ngx_http_dav_module. These flaws can lead to Denial of Service (DoS) attacks, allowing attackers to crash the server or execute arbitrary code. Specifically, CVE-2026-32647 and CVE-2026-27784 highlight risks of memory corruption and DoS, while CVE-2026-27654 and CVE-2026-27651 expose the system to file modification and undisclosed request vulnerabilities when certain modules are enabled.
How To Fix
Minimum fixed version
2:1.20.1-24.el9_7.2.alma.1
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
As a temporary workaround, consider disabling the ngx_mail_auth_http_module if it is not needed, to mitigate the risk of undisclosed requests leading to DoS attacks.
Conclusion
The identified vulnerabilities in nginx pose significant risks, including Denial of Service and potential code execution. It is crucial for users to update to the latest patched versions to safeguard their systems. Implementing workarounds and utilizing tools like Vulert can further enhance security measures.
See every vulnerability recorded for nginx →
FAQ
The vulnerabilities can lead to Denial of Service attacks, allowing attackers to crash the server or execute arbitrary code, compromising the security of the system.
You can use Vulert to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected without requiring signup.
If immediate updates are not possible, consider disabling vulnerable modules or implementing strict access controls to limit exposure.
While specific exploits may not be publicly disclosed, the nature of the vulnerabilities suggests that they could be exploited by attackers to disrupt services or gain unauthorized access.
Regularly check for vulnerabilities, ideally on a weekly basis, and subscribe to security bulletins for the software you use to stay informed about new vulnerabilities.
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