Apache HTTP Server 2.4.46 contains 8 documented vulnerabilities, including 2 critical flaws that pose serious security risks to your website. With nearly 500 websites still running this outdated version, the threat landscape is significant and immediate action is required. This comprehensive guide will help you understand these vulnerabilities, identify if your server is affected, and implement essential security patches.
The vulnerabilities range from heap overflows that could allow remote code execution to denial-of-service attacks that can crash your web server. Even medium-severity issues can be exploited to disrupt service or gain unauthorized access. Understanding these threats is the first step toward protecting your digital assets.
Whether you're a system administrator, IT manager, or website owner, this guide provides the technical knowledge you need to secure your Apache infrastructure quickly and effectively.
Apache HTTP Server is one of the most popular open-source web servers in the world, powering millions of websites across the internet. Version 2.4.46, released in 2020, was intended to be a stable release but was later found to contain multiple security flaws. Apache handles all the HTTP requests that come to your website and serves your web pages to visitors—making it a critical component of your online presence.
Apache 2.4.46 is particularly vulnerable because it processes various types of requests and headers that can be manipulated by attackers. When security vulnerabilities exist in this core component, malicious actors can exploit them to crash your server, steal sensitive data, or gain unauthorized access to your systems. This is why keeping Apache updated and patched is essential for maintaining website security and availability.
8 CVEs found. The most critical are explained below.
An attacker can send specially crafted session information to your web server that causes it to use more memory than allocated. This is a critical vulnerability because it can lead to complete server compromise or takeover.
Impact: Your website could crash, be taken offline, or an attacker could potentially run malicious code on your server with full control.
↗ View on NVDApache version 2.4.46 contains several unspecified security problems that need to be addressed. Since details are limited, assume this could affect the core functionality of your web server.
Impact: Your server could be vulnerable to various attacks that compromise security, performance, or availability.
↗ View on NVDAn attacker can craft a specific type of web request that causes your Apache server to crash immediately. The server needs both Content-Length and Transfer-Encoding headers in a certain way to trigger the problem.
Impact: Your website becomes unavailable (Denial of Service attack), causing downtime and lost business until the server is manually restarted.
↗ View on NVDAn attacker can send a specially crafted cookie to your web server that causes it to crash immediately. This is a denial of service attack that requires no authentication.
Impact: Your website goes down without warning, affecting all visitors and customers until you manually restart the server.
↗ View on NVDA malicious digest authentication nonce (a security token) could cause Apache's authentication module to overflow memory. While security experts haven't confirmed this is actually exploitable in practice, certain server configurations might make it dangerous.
Impact: If exploitable, your server could crash or potentially be compromised, but current evidence suggests this is unlikely in most setups.
↗ View on NVDOn Windows servers only, any regular user with local access to the computer can stop Apache from running. This only affects Windows systems and requires physical or local network access.
Impact: Someone with local computer access could shut down your website, but this requires being inside your network or having access to your server physically.
↗ View on NVDShowing first 10 of 2. View all on NVD ↗
| CVE ID | Severity | Score | Published | Description |
|---|---|---|---|---|
| CVE-2019-17567 | MEDIUM | 5.3 | 2021-06-10 | Apache HTTP Server versions 2.4.6 to 2.4.46 mod_proxy_wstunnel configured on an URL that is not necessarily Upgraded by the origin server was tunneling the whole connection regard… |
| CVE-2021-30641 | MEDIUM | 5.3 | 2021-06-10 | Apache HTTP Server versions 2.4.39 to 2.4.46 Unexpected matching behavior with 'MergeSlashes OFF' |
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Apache 2.4.46 poses significant security risks with its 2 critical and 3 high-severity vulnerabilities. The potential for heap overflows, denial-of-service attacks, and NULL pointer dereference exploits means that delaying an update is simply not an option. By following the steps outlined in this guide, you can quickly patch your server and eliminate these known threats.
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