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Home / Blog / Apache 2
Security Advisory

Apache 2 Security: 1,097 CVEs Affecting 10,501 Websites

📅 June 07, 2026 ·⏱ 5 min read ·🔒 SiteRecipe Security Team
10,501 websites still running Apache 2  → View full list
1097
Total
178
Critical
386
High
500
Medium
28
Low

Apache 2 powers over 10,500 websites worldwide, making it one of the most widely deployed web servers on the internet. However, this popularity also makes it a prime target for cybercriminals. Our research has identified 1,097 known vulnerabilities in Apache 2, including 178 critical-severity flaws that could lead to complete server compromise, data theft, and unauthorized access.

If your website runs on Apache 2, you could be at immediate risk. Critical vulnerabilities like CVE-2021-44228 (the Log4j2 exploit) and CVE-2009-3555 (TLS protocol flaw) have been actively exploited in real-world attacks. The good news? Most vulnerabilities are preventable with proper patching and configuration hardening.

This guide will walk you through identifying vulnerable Apache 2 installations, understanding the top threats, and implementing fixes to secure your server.

What is Apache 2?

Apache 2 (Apache HTTP Server version 2.x) is a free, open-source web server that serves websites and applications across the internet. It's known for its reliability, flexibility, and ability to handle high traffic loads. Apache 2 works by receiving requests from users' browsers and delivering web content—everything from HTML pages to dynamic applications. Organizations choose Apache 2 because it's stable, well-documented, and runs on virtually every operating system.

Like any software, Apache 2 requires ongoing maintenance and security updates. Vulnerabilities are discovered regularly in Apache 2 itself and in the libraries it depends on (like Log4j2 and Commons Configuration). When a vulnerability is discovered, Apache releases a patch. However, many website administrators delay or skip updates, leaving their servers exposed. This creates a significant security gap that attackers actively exploit.

Key Vulnerabilities in Apache 2

1097 CVEs found. The most critical are explained below.

CRITICAL CVE-2020-1953 10.0/10 · CVSS v3.1 ⏱ Within 7 days
Apache Commons Configuration YAML File Injection

Apache Commons Configuration has a vulnerability where it can be tricked into running malicious code hidden inside YAML configuration files. If your website processes YAML files from untrusted sources, attackers could inject commands that execute on your server.

Impact: An attacker could gain control of your server, steal data, install malware, or shut down your website.

↗ View on NVD
CRITICAL CVE-2021-44228 10.0/10 · CVSS v3.1 ⏱ Immediate
Apache Log4j2 Remote Code Execution Vulnerability

Log4j2 is logging software that many Apache applications use to record events. This critical flaw allows attackers to execute code remotely by embedding malicious instructions in log messages. This is one of the most serious vulnerabilities discovered in recent years.

Impact: Attackers can take complete control of your server without needing any special access. This vulnerability has been actively exploited in the wild.

↗ View on NVD
CRITICAL CVE-2009-3555 9.8/10 · CVSS v3.1 ⏱ Immediate
TLS/SSL Encryption Handshake Vulnerability

This vulnerability exists in the encrypted connection process between your website and visitors' browsers. An attacker can manipulate this initial conversation to intercept or modify data that should be secure.

Impact: Visitor data including passwords and payment information could be intercepted or modified during transmission, compromising customer security.

↗ View on NVD
CRITICAL CVE-2010-2076 9.8/10 · CVSS v3.1 ⏱ Immediate
Apache CXF XML External Entity Injection

Apache CXF processes XML messages from web services but doesn't properly validate them. An attacker can craft special XML messages that trick your server into reading files it shouldn't or making unauthorized network requests.

Impact: Sensitive files could be exposed, your server could be used to attack other systems, or internal data could be stolen.

↗ View on NVD
CRITICAL CVE-2012-0391 9.8/10 · CVSS v3.1 ⏱ Immediate
Apache Struts Exception Handling Code Execution

Apache Struts has a weakness in how it handles errors. When the application encounters certain errors, it incorrectly processes user input as executable code rather than just text data.

Impact: Attackers can execute arbitrary code on your server by submitting specially crafted form data, potentially compromising your entire website.

↗ View on NVD
CRITICAL CVE-2013-2251 9.8/10 · CVSS v3.1 ⏱ Immediate
Apache Struts Expression Language Injection

Apache Struts allows attackers to inject malicious expressions into web requests. These expressions are interpreted as code instructions rather than normal user input, allowing remote code execution.

Impact: Attackers can execute any code they want on your server without authentication, giving them complete control over your website and data.

↗ View on NVD

Additional Vulnerabilities (1091 more)

Showing first 10 of 1091. View all on NVD ↗

CVE IDSeverityScore PublishedDescription
CVE-2015-3253 CRITICAL 9.8 2015-08-13 The MethodClosure class in runtime/MethodClosure.java in Apache Groovy 1.7.0 through 2.4.3 allows remote attackers to execute arbitrary code or cause a denial of service via a cra…
CVE-2015-5344 CRITICAL 9.8 2016-02-03 The camel-xstream component in Apache Camel before 2.15.5 and 2.16.x before 2.16.1 allow remote attackers to execute arbitrary commands via a crafted serialized Java object in an …
CVE-2016-3082 CRITICAL 9.8 2016-04-26 XSLTResult in Apache Struts 2.x before 2.3.20.2, 2.3.24.x before 2.3.24.2, and 2.3.28.x before 2.3.28.1 allows remote attackers to execute arbitrary code via the stylesheet locati…
CVE-2016-1114 CRITICAL 9.8 2016-05-11 Adobe ColdFusion 10 before Update 19, 11 before Update 8, and 2016 before Update 1 allows remote attackers to execute arbitrary commands via a crafted serialized Java object, rela…
CVE-2016-3087 CRITICAL 9.8 2016-06-07 Apache Struts 2.3.19 to 2.3.20.2, 2.3.21 to 2.3.24.1, and 2.3.25 to 2.3.28, when Dynamic Method Invocation is enabled, allow remote attackers to execute arbitrary code via vectors…
CVE-2016-4438 CRITICAL 9.8 2016-07-04 The REST plugin in Apache Struts 2 2.3.19 through 2.3.28.1 allows remote attackers to execute arbitrary code via a crafted expression.
CVE-2016-4436 CRITICAL 9.8 2016-10-03 Apache Struts 2 before 2.3.29 and 2.5.x before 2.5.1 allow attackers to have unspecified impact via vectors related to improper action name clean up.
CVE-2016-5019 CRITICAL 9.8 2016-10-03 CoreResponseStateManager in Apache MyFaces Trinidad 1.0.0 through 1.0.13, 1.2.x before 1.2.15, 2.0.x before 2.0.2, and 2.1.x before 2.1.2 might allow attackers to conduct deserial…
CVE-2017-5638 CRITICAL 9.8 2017-03-11 The Jakarta Multipart parser in Apache Struts 2 2.3.x before 2.3.32 and 2.5.x before 2.5.10.1 has incorrect exception handling and error-message generation during file-upload atte…
CVE-2017-5645 CRITICAL 9.8 2017-04-17 In Apache Log4j 2.x before 2.8.2, when using the TCP socket server or UDP socket server to receive serialized log events from another application, a specially crafted binary paylo…
Full Report Available

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Conclusion

Apache 2 remains a trusted web server platform, but its security depends entirely on keeping it updated. With 178 critical vulnerabilities identified and 10,501 websites still using vulnerable versions, the risk is real and immediate. Attackers are actively scanning for unpatched Apache servers to exploit flaws like Log4j2 injection, OGNL expression injection, and TLS protocol bypass attacks.

The solution is simple: update now and monitor continuously. SiteRecipe.com provides automated vulnerability scanning, patch management, and security recommendations specifically designed for Apache 2 environments. Our platform scans your website against the entire CVE database, identifies exploitable weaknesses, and guides you through remediation step-by-step. Don't wait for a breach to happen—secure your Apache 2 server today with SiteRecipe.com's comprehensive security analysis.

Frequently Asked Questions

How often are Apache 2 vulnerabilities discovered?
Apache 2 vulnerabilities are discovered regularly—sometimes multiple per month. Critical vulnerabilities are typically patched within weeks, but dependent libraries like Log4j2 may have longer disclosure timelines. Most organizations miss updates because they lack continuous monitoring, which is why automated scanning is essential.
Can I be exploited if I run an old Apache 2 version?
Yes, absolutely. Attackers actively exploit known, unpatched vulnerabilities because they're predictable and widely documented. CVE-2009-3555 (from 2009) and CVE-2013-2251 (from 2013) are still exploited today against servers running outdated versions. Immediate patching is critical.
What's the difference between a critical and high-severity CVE?
Critical CVEs allow remote code execution (attacker gains complete server control), while high-severity vulnerabilities may allow data theft, denial of service, or privilege escalation. Both require urgent patching, but critical vulnerabilities pose the greatest immediate threat to your website.
Will updating Apache 2 break my website?
Major version updates (2.2 to 2.4) may require configuration changes, but minor and patch updates are designed to be backward compatible. Always test updates on a staging server first, and keep backups of your configuration. SiteRecipe.com helps identify potential compatibility issues before you apply patches.
How do I know if my server has been compromised?
Signs of compromise include unusual processes running on your server, unexpected changes to files, unexplained traffic spikes, or unexpected outages. However, sophisticated attacks may leave no visible traces. Regular vulnerability scans with SiteRecipe.com can detect exploitation attempts and weaknesses before they're fully leveraged.

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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