Critical Apache HTTP Server Bugs Allow Remote Code Execution
Key Takeaways The Apache Software Foundation released Apache HTTP Server version 2.4.69 on October 1, 2026, addressing 20 security vulnerabilities. These flaws could lead to remote code execution,...
Key Takeaways
- The Apache Software Foundation released Apache HTTP Server version 2.4.69 on October 1, 2026, addressing 20 security vulnerabilities.
- These flaws could lead to remote code execution, server crashes, information disclosure, and authentication bypass under specific, non-default configurations.
- Two critical remote code execution vulnerabilities (CVE-2026-63292, CVE-2026-42356) are present but require particular server settings and attacker conditions to exploit.
- Five vulnerabilities are rated “Moderate,” and fifteen are rated “Low” in severity.
- Administrators are strongly advised to upgrade to Apache HTTP Server 2.4.69 immediately.
Apache HTTP Server Patches Critical Flaws, Including Conditional RCE
The Apache Software Foundation has issued a significant security update, releasing Apache HTTP Server 2.4.69 on October 1, 2026. This new version addresses a total of 20 security vulnerabilities, some of which could potentially allow remote code execution, lead to server instability, enable data leaks, or facilitate authentication bypasses under specific environmental conditions. Apache has designated this release as the definitive and most secure version of its widely used web server to date.
Table Of Content
The comprehensive advisory accompanying the update details five vulnerabilities categorized as moderate severity and fifteen as low severity. While most of these issues impact versions 2.4.0 through 2.4.68, the actual risk to a given deployment is contingent upon the modules enabled, specific server configurations, and the attacker’s access vectors. It is crucial to understand that the identified remote code execution risks come with notable prerequisites and do not represent a universal threat to every Apache installation.
Detailed Vulnerability Breakdown
Among the more severe findings is CVE-2026-63292, affecting the mod_vhost_alias module. A malicious remote client could trigger a server crash or potentially achieve code execution by submitting a Host header exceeding 8,192 bytes. Successful exploitation of this vulnerability requires the VirtualDocumentRoot directive to utilize a hostname format specifier, alongside a non-default configuration where LimitRequestFieldSize has been increased beyond its default setting.
Another significant issue, CVE-2026-42356, concerns Apache’s handler selection process following specific internal redirects originating from CGI programs. In certain scenarios, a redirected file could be executed as a CGI script. However, this exploit path is highly constrained: the target file must already reside within a CGI-enabled directory and must not possess an extension recognized by mod_mime. This particular vulnerability affects Apache HTTP Server versions 2.4.60 through 2.4.68.
It is important to reiterate that the conditions for exploiting both CVE-2026-63292 and CVE-2026-42356 are specific and do not equate to unconstrained remote code execution against standard, default Apache deployments. This contrasts with earlier Apache HTTP Server vulnerabilities, such as a separate HTTP/2 double-free flaw that was addressed in version 2.4.67.
Summary of Vulnerabilities Addressed in Apache HTTP Server 2.4.69
The following table provides a concise overview of the vulnerabilities detailed in the Apache security advisory. Unless explicitly noted otherwise, the affected versions span 2.4.0 through 2.4.68, and all listed fixes are incorporated into version 2.4.69.
| CVE | Module or component | Severity | Vulnerability or impact |
|---|---|---|---|
| CVE-2026-42356 | CGI handling | Low | Limited code execution; 2.4.60–2.4.68. |
| CVE-2026-42528 | mod_dav | Moderate | Shared-lock overflow crashes child processes; through 2.4.68.* |
| CVE-2026-46729 | mod_heartmonitor | Low | Null pointer crash on unicast listener |
| CVE-2026-47360 | mod_session_cookie | Low | Session cookies reach backend after redirects. |
| CVE-2026-48005 | mod_auth_digest | Low | Forged headers force reauthentication |
| CVE-2026-56153 | mod_charset_lite | Low | Heap overflow in finish_partial_char |
| CVE-2026-56154 | mod_rewrite | Low | Use-after-free during lookahead |
| CVE-2026-56449 | mod_proxy_html | Low | Crafted response causes out-of-bounds write |
| CVE-2026-57941 | mod_http2 | Moderate | Shared-buffer use-after-free and memory write |
| CVE-2026-58415 | mod_dav_fs | Low | WebDAV property database disclosure |
| CVE-2026-59685 | Windows path handling | Moderate | Out-of-bounds write expanding short filenames. |
| CVE-2026-59797 | mod_ssl | Low | Privilege handling flaw in SSLRequire expressions. |
| CVE-2026-63045 | mod_proxy_ftp | Low | Crafted PASV reply redirects data connections. |
| CVE-2026-63292 | mod_vhost_alias | Moderate | Stack overflow; crashes or possible code execution. |
| CVE-2026-63686 | mod_xml2enc | Low | Failed charset conversion crashes proxy processing. |
| CVE-2026-63718 | mod_proxy_uwsgi | Low | Response smuggling; 2.4.30–2.4.68 |
| CVE-2026-73636 | mod_auth_digest | Low | Captured authentication credentials can be replayed |
| CVE-2026-73637 | mod_auth_digest | Low | Concurrent requests corrupt authentication state |
| CVE-2026-79768 | mod_userdir | Low | Information disclosure through path equivalence. |
| CVE-2026-93546 | mod_dav_fs | Moderate | Namespace overflow; crashes and database corruption; through 2.4.68. |
Users leveraging WebDAV functionalities face specific risks related to availability and data integrity. CVE-2026-93546 allows an authenticated client with write permissions to crash worker processes and potentially corrupt a directory’s property database persistently. This can occur through specially crafted PROPPATCH requests that declare an excessive number of XML namespaces.
Apache installations configured as proxies also require immediate attention. CVE-2026-63045 enables an untrusted FTP server to redirect a forward proxy’s data connection to an unintended external host. Furthermore, CVE-2026-47360 could lead to session cookies being inadvertently passed to backend servers, even when internal redirects were designed to prevent such transmission.
What You Should Do
- Upgrade Immediately: Apply the Apache HTTP Server 2.4.69 update as soon as possible. This is the primary and most effective mitigation for all identified vulnerabilities.
- Review Configurations: After upgrading, meticulously review your Apache server configurations to determine if any of the specific vulnerable settings (e.g., virtual host configurations, CGI redirect setups, WebDAV features) are present in your environment.
- Prioritize Critical Servers: Give top priority to upgrading servers that utilize the vulnerable virtual-host settings, rely on CGI redirects, or actively employ WebDAV functionalities, as these are exposed to higher-impact risks.
- Consult Advisories: Always refer to the official Apache security advisory and individual CVE records for the most current information regarding affected versions and any subsequent corrections. Be aware that the security impact of these vulnerabilities can vary depending on the operating system and platform.
Disclaimer: HackersRadar reports on cybersecurity threats and incidents for informational and awareness purposes only. We do not engage in hacking activities, data exfiltration, or the hosting or distribution of stolen or leaked information. All content is based on publicly available sources.
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