Server-Side Request Forgery (SSRF) in Apache HTTP Server on Windows allows to potentially leak NTLM hashes to a malicious server via mod_rewrite or apache expressions that pass unvalidated request input. This issue affects Apache HTTP Server: from 2.4.0 through 2.4.63. Note: The Apache HTTP Server Project will be setting a higher bar for accepting vulnerability reports regarding SSRF via UNC paths. The server offers limited protection against administrators directing the server to open UNC paths. Windows servers should limit the hosts they will connect over via SMB based on the nature of NTLM authentication.

An update of the httpd package has been released.

The remote Debian 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4270 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-4270-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                   Bastien Roucaris     August 12, 2025                               https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : apache2     Version        : 2.4.65-1~deb11u1     CVE ID         : CVE-2024-42516 CVE-2024-43204 CVE-2024-43394 CVE-2024-47252                      CVE-2025-23048 CVE-2025-49630 CVE-2025-49812 CVE-2025-53020                      CVE-2025-54090

    Multiple vulnerabilities have been addressed in Apache,     a widely used web server.

    Please note that the fix for CVE-2025-23048, included in this DLA,     may cause some SSL-enabled websites to encounter the error AH02032.
    Additional details are provided at the end of this advisory.

    CVE-2024-42516

        HTTP response splitting in the core of Apache HTTP Server allows an         attacker who can manipulate the Content-Type response headers of         applications hosted or proxied by the server can split the HTTP response

    CVE-2024-43204

        A SSRF (Server Side Request Forgery) was found in Apache HTTP Server         with mod_proxy loaded allows an attacker to         send outbound proxy requests to a URL controlled by the attacker.
        This attack requires an unlikely configuration where mod_headers         is configured to modify the Content-Type request or response header with a         value provided in the HTTP request

    CVE-2024-43394

        A Server-Side Request Forgery (SSRF) in Apache HTTP Server on Windows         allows to potentially leak NTLM hashes to a malicious server via  mod_rewrite         or apache expressions that pass unvalidated request input.

    CVE-2024-47252

        Insufficient escaping of user-supplied data in mod_ssl allows an untrusted         SSL/TLS client to insert escape characters into log files in some         configurations. In a logging configuration where CustomLog is used with         %{varname}x or %{varname}c to log variables provided by mod_ssl such as         SSL_TLS_SNI, no escaping is performed by either mod_log_config or mod_ssl and         unsanitized data provided by the client may appear in log files.

    CVE-2025-23048

        An access control bypass by trusted clients is possible using TLS 1.3         session resumption. Configurations are affected when mod_ssl is         configured for multiple virtual hosts, with each restricted to a         different set of trusted client certificates         (for example with a different SSLCACertificateFile/Path setting).
        In such a case, a client trusted to access one virtual host may be able to         access another virtual host, if SSLStrictSNIVHostCheck is not enabled         in either virtual host.

    CVE-2025-49630

        In certain proxy configurations, a denial of service attack against         Apache HTTP Server can be triggered by untrusted clients causing         an assertion in mod_proxy_http2. Configurations affected are a         reverse proxy is configured for an HTTP/2 backend, with         ProxyPreserveHost set to on.

    CVE-2025-49812

        In some mod_ssl configurations on Apache HTTP server, an HTTP         desynchronisation attack allows a man-in-the-middle attacker         to hijack an HTTP session via a TLS upgrade. Only configurations         using SSLEngine optional to enable TLS upgrades are affected.
        Support for TLS upgrade was removed.

    CVE-2025-53020

        A late Release of Memory after Effective Lifetime vulnerability         was found in Apache HTTP Server.

    CVE-2025-54090

        A bug in Apache HTTP Server 2.4.64 results in all         RewriteCond expr ... tests evaluating as true

    For Debian 11 bullseye, these problems have been fixed in version     2.4.65-1~deb11u1.

    Note that following the resolution of CVE-2025-23048,     some SSL-enabled websites may begin encountering     the error (AH02032):

        Misdirected Request:
        The client needs a new connection for this request as the         requested host name does not match the Server Name Indication         (SNI) in use for this connection.

    This behavior is particularly noticeable with AWS Application     Load Balancers. Although they support intelligent SNI handling,     they do not (as of this writing) relay SNI data to the target     server, resulting in failed connections when hostnames don??t align.

    Without an SNI provided by the client, there is nothing httpd     can do to determine which vhost/configuration should be     used to provide the correct certificate (and TLS authentication     eventually) whenever multiple vhosts listen on the same IP:port.

    That's because reading the HTTP Host header necessarily has to     happen after the TLS handshake/auth/decryption (and later     renegotiation is not an option with TLSv1.3).

    So those connections fall back to the first vhost declared on     the IP:port for the TLS handshake part, and if the request     Host header finally matches a different vhost with a different     TLS configuration it's rejected with AH02032.

    Before 2.4.64 the check was not accurate and would allow that,     with security implications.

    As a workaround, you may (after a risk analysis) generate a     wildcard certificate. If you??re managing multiple domains,     consolidate them into a single certificate by including each     wildcard domain as an alias. Then, update the Apache configuration     to reference this unified certificate.

    Another possible workaround is to configure each virtual host to     listen on a separate port. This approach avoids SNI-related issues     by ensuring that each vhost is uniquely addressed through its own     connection endpoint, thereby allowing distinct TLS configurations     without ambiguity.

    This error may also stem from a misconfigured HAProxy setup.
    In such cases, enabling dynamic SNI handling on HAProxy might be     necessary to ensure that the correct hostname is passed through     during the TLS handshake. After risk analysis, it could be done     by using sni req.hdr(Host) directive.

    We recommend that you upgrade your apache2 packages.

    For the detailed security status of apache2 please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/apache2

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Server-Side Request Forgery (SSRF) in Apache HTTP Server on Windows allows to potentially leak NTLM hashes     to a malicious server via mod_rewrite or apache expressions that pass unvalidated request input. This     issue affects Apache HTTP Server: from 2.4.0 through 2.4.63. Note: The Apache HTTP Server Project will be     setting a higher bar for accepting vulnerability reports regarding SSRF via UNC paths. The server offers     limited protection against administrators directing the server to open UNC paths. Windows servers should     limit the hosts they will connect over via SMB based on the nature of NTLM authentication.
    (CVE-2024-43394)

Note that Nessus relies on the presence of the package as reported by the vendor.

The version of httpd installed on the remote host is prior to 2.4.65. It is, therefore, affected by multiple vulnerabilities as referenced in the SSA:2025-204-01 advisory.

    New httpd packages are available for Slackware 15.0 and -current to fix security issues.

Tenable has extracted the preceding description block directly from the httpd security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

According to its banner, the version of Apache running on the remote host is 2.4.x prior to 2.4.64. It is, therefore, affected by multiple vulnerabilities:

 - HTTP response splitting in the core of Apache HTTP Server allows an attacker who can manipulate the Content-Type response headers of applications hosted or proxied by the server can split the HTTP response. (CVE-2024-42516)

 - Server-Side Request Forgery (SSRF) in Apache HTTP Server with mod_proxy loaded allows an attacker to send outbound proxy requests to a URL controlled by the attacker. (CVE-2024-43204)

 - Server-Side Request Forgery (SSRF) in Apache HTTP Server on Windows allows to potentially leak NTLM hashes to a malicious server via mod_rewrite or apache expressions that pass unvalidated request input. (CVE-2024-43394)

 - Insufficient escaping of user-supplied data in mod_ssl in Apache HTTP Server 2.4.63 and earlier allows an untrusted SSL/TLS client to insert escape characters into log files in some configurations. (CVE-2024-47252)

 - In some mod_ssl configurations on Apache HTTP Server 2.4.35 through to 2.4.62, an access control bypass by trusted clients is possible using TLS 1.3 session resumption. (CVE-2025-23048)

 - In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2. (CVE-2025-49630)

 - In some mod_ssl configurations on Apache HTTP Server versions through to 2.4.63, an HTTP desynchronisation attack allows a man-in-the-middle attacker to hijack an HTTP session via a TLS upgrade. (CVE-2025-49812)

 - Late Release of Memory after Effective Lifetime vulnerability in Apache HTTP Server. (CVE-2025-53020) Note that the scanner has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the 342f2a0a-5e9b-11f0-8baa-8447094a420f advisory.

    The Apache httpd project reports:
    moderate: Apache HTTP Server: HTTP response splitting (CVE-2024-42516)     low: Apache HTTP Server: SSRF with mod_headers setting Content-Type header (CVE-2024-43204)     moderate: Apache HTTP Server: SSRF on Windows due to UNC paths (CVE-2024-43394)     low: Apache HTTP Server: mod_ssl error log variable escaping (CVE-2024-47252)     moderate: Apache HTTP Server: mod_ssl access control bypass with session resumption (CVE-2025-23048)     low: Apache HTTP Server: mod_proxy_http2 denial of service (CVE-2025-49630)     moderate: Apache HTTP Server: mod_ssl TLS upgrade attack (CVE-2025-49812)     moderate: Apache HTTP Server: HTTP/2 DoS by Memory Increase (CVE-2025-53020)

Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of httpd installed on the remote host is prior to 2.4.64. It is, therefore, affected by multiple vulnerabilities as referenced in the SSA:2025-192-02 advisory.

    New httpd packages are available for Slackware 15.0 and -current to fix security issues.

Tenable has extracted the preceding description block directly from the httpd security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of Apache httpd installed on the remote host is prior to 2.4.64. It is, therefore, affected by multiple vulnerabilities as referenced in the 2.4.64 advisory.

  - In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26     through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2.
    Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost     set to on. (CVE-2025-49630)

  - HTTP response splitting in the core of Apache HTTP Server allows an attacker who can manipulate the     Content-Type response headers of applications hosted or proxied by the server can split the HTTP response.
    This vulnerability was described as CVE-2023-38709 but the patch included in Apache HTTP Server 2.4.59 did     not address the issue. Users are recommended to upgrade to version 2.4.64, which fixes this issue.
    (CVE-2024-42516)

  - SSRF in Apache HTTP Server with mod_proxy loaded allows an attacker to send outbound proxy requests to a     URL controlled by the attacker. Requires an unlikely configuration where mod_headers is configured to     modify the Content-Type request or response header with a value provided in the HTTP request. Users are     recommended to upgrade to version 2.4.64 which fixes this issue. (CVE-2024-43204)

  - Server-Side Request Forgery (SSRF) in Apache HTTP Server on Windows allows to potentially leak NTLM hashes     to a malicious server via mod_rewrite or apache expressions that pass unvalidated request input. This     issue affects Apache HTTP Server: from 2.4.0 through 2.4.63. Note: The Apache HTTP Server Project will be     setting a higher bar for accepting vulnerability reports regarding SSRF via UNC paths. The server offers     limited protection against administrators directing the server to open UNC paths. Windows servers should     limit the hosts they will connect over via SMB based on the nature of NTLM authentication.
    (CVE-2024-43394)

  - Insufficient escaping of user-supplied data in mod_ssl in Apache HTTP Server 2.4.63 and earlier allows an     untrusted SSL/TLS client to insert escape characters into log files in some configurations. In a logging     configuration where CustomLog is used with %{varname}x or %{varname}c to log variables provided by     mod_ssl such as SSL_TLS_SNI, no escaping is performed by either mod_log_config or mod_ssl and unsanitized     data provided by the client may appear in log files. (CVE-2024-47252)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
251227	Photon OS 5.0: Httpd PHSA-2025-5.0-0570	Nessus	PhotonOS Local Security Checks	critical
249166	Debian dla-4270 : apache2 - security update	Nessus	Debian Local Security Checks	critical
244700	Linux Distros Unpatched Vulnerability : CVE-2024-43394	Nessus	Misc.	high
242640	Slackware Linux 15.0 / current httpd Multiple Vulnerabilities (SSA:2025-204-01)	Nessus	Slackware Local Security Checks	critical
114917	Apache 2.4.x < 2.4.64 Multiple Vulnerabilities	Web App Scanning	Component Vulnerability	critical
242028	FreeBSD : Apache httpd -- Multiple vulnerabilities (342f2a0a-5e9b-11f0-8baa-8447094a420f)	Nessus	FreeBSD Local Security Checks	high
242008	Slackware Linux 15.0 / current httpd Multiple Vulnerabilities (SSA:2025-192-02)	Nessus	Slackware Local Security Checks	high
241984	Apache 2.4.x < 2.4.64 Multiple Vulnerabilities	Nessus	Web Servers	high

Detections

Analytics

CVE-2024-43394

high

Tenable Plugins

critical

critical

high

critical

critical

high

high

high