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Home / Blog / Apache 2.4.37
Security Advisory

Apache 2.4.37: 4 Critical Vulnerabilities Affecting 612 Sites

📅 June 07, 2026 ·⏱ 5 min read ·🔒 SiteRecipe Security Team
612 websites still running Apache 2.4.37  → View full list
4
Total
3
High
1
Medium

Apache HTTP Server 2.4.37 is currently running on 612 websites, but it contains 4 known vulnerabilities including 3 rated as HIGH severity. These flaws could allow attackers to bypass security controls, hijack user sessions, and cause denial of service attacks. If your website uses this outdated version, you're at significant risk and need to take immediate action.

This comprehensive guide will help you understand the vulnerabilities affecting Apache 2.4.37, identify whether your server is vulnerable, and implement the necessary patches to protect your website. We'll walk you through each CVE, explain the real-world implications, and provide step-by-step remediation instructions.

Time is critical—cybercriminals actively exploit known vulnerabilities in popular software like Apache. Delaying updates increases your exposure to breaches, data theft, and compliance violations.

What is Apache 2.4.37?

Apache HTTP Server 2.4.37 is a web server software that powers websites by handling requests from visitors' browsers and delivering web pages. Released in 2018, this version was once considered secure, but subsequent security research discovered multiple critical flaws. Apache 2.4.37 uses modules like mod_ssl for HTTPS encryption, mod_session for user authentication, and mod_http2 for modern HTTP/2 protocol support.

Think of Apache as the 'middleman' between your website visitors and your website files. It receives billions of requests daily across millions of websites worldwide. When vulnerabilities exist in Apache, attackers can exploit them to intercept sensitive data, steal session tokens, or crash your entire website. The four vulnerabilities in version 2.4.37 are particularly dangerous because they affect core security features that protect user data.

Key Vulnerabilities in Apache 2.4.37

4 CVEs found. The most critical are explained below.

HIGH CVE-2018-17199 7.5/10 · CVSS v3.0 ⏱ Within 30 days
Session expiration bypass in cookie-based sessions

Your website's temporary login sessions aren't expiring when they should. An attacker could use an expired session cookie to stay logged in longer than intended. This only affects websites using Apache's cookie-based session management.

Impact: Users could remain authenticated after their session should have ended, potentially allowing unauthorized access to their accounts or data.

↗ View on NVD
HIGH CVE-2019-0190 7.5/10 · CVSS v3.1 ⏱ Immediate
Server crash vulnerability in SSL connections

Attackers can send specially crafted requests that cause your web server to get stuck in an infinite loop and stop responding. This vulnerability only affects Apache 2.4.37 paired with OpenSSL 1.1.1 or newer versions.

Impact: Your website could become unavailable (down) until the server is manually restarted, affecting all visitors.

↗ View on NVD
HIGH CVE-2019-0215 7.5/10 · CVSS v3.0 ⏱ Immediate
Client certificate security bypass with modern encryption

Websites requiring client certificates for security (like those protecting sensitive areas) could be bypassed by attackers. This only happens on Apache 2.4.37-2.4.38 with the newest TLS 1.3 encryption standard.

Impact: Attackers could gain access to restricted areas that should require valid client certificates, exposing protected content.

↗ View on NVD
MEDIUM CVE-2018-17189 5.3/10 · CVSS v3.1 ⏱ Within 7 days
Slow upload requests disable server responsiveness

Attackers can deliberately send data very slowly to tie up your server's resources. Your server dedicates worker threads to process these slow requests, leaving fewer resources for legitimate visitors.

Impact: Your website could become slow or unresponsive when attacked, reducing availability for real users.

↗ View on NVD

Is your website running Apache 2.4.37?

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How to Check If Your Website Is Affected

How to Fix These Vulnerabilities

Conclusion

Apache 2.4.37 contains serious security flaws that put your website and visitors at risk. The three HIGH severity vulnerabilities allow attackers to bypass SSL security, hijack user sessions, and exploit authentication mechanisms. With 612 websites still running this vulnerable version, you can be certain that attackers are actively scanning for and exploiting these flaws. Updating to Apache 2.4.39 or later is not optional—it's a critical security requirement.

Don't leave your website vulnerable to exploitation. Use SiteRecipe.com to scan your entire server infrastructure for outdated software, unpatched vulnerabilities, and security misconfigurations. Our automated tools identify all CVEs affecting your systems, prioritize them by severity, and provide remediation guidance tailored to your environment. Start your free security scan today at SiteRecipe.com and take control of your server's security.

Frequently Asked Questions

Is Apache 2.4.37 still receiving security updates?
No. Apache 2.4.37 reached end-of-life in 2018 and no longer receives official security patches. Only versions 2.4.39 and later receive active maintenance. Continuing to use 2.4.37 means you'll never receive fixes for these vulnerabilities.
Can I update Apache without downtime?
Yes, with proper planning. You can update Apache while keeping your website running by using a load balancer to redirect traffic, updating servers one at a time, or scheduling the update during low-traffic hours. Always backup your configuration first.
Will updating Apache break my website?
Updating to a newer 2.4.x version is generally safe since minor version updates maintain compatibility. However, always test updates in a staging environment first, especially if you use custom Apache modules or have complex configurations.
How serious is CVE-2019-0215 (SSL bypass)?
This is extremely serious. It allows attackers to bypass client certificate verification on HTTPS connections, potentially giving unauthorized users access to restricted areas. Any website using per-location certificate requirements is at critical risk.
Can a firewall protect me from these Apache vulnerabilities?
A firewall cannot fully protect you from these vulnerabilities because they occur at the application layer within Apache itself. While a WAF (Web Application Firewall) may help mitigate some attacks, updating Apache is the only reliable solution.

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DISCLAIMER: This report is based on publicly available CVE data from the National Vulnerability Database (NVD) maintained by NIST. Detection of a technology version does not confirm active exploitation on any specific website. For informational purposes only. SiteRecipe is not responsible for actions taken based on this report. Always consult a qualified security professional.

Source: nvd.nist.gov · Published: June 07, 2026 · SiteRecipe.com