Apache HTTP Server SSRF via mod_rewrite/expressions (2.4.0-2.4.63)
CVE-2024-43394 Published on July 10, 2025
Apache HTTP Server: SSRF on Windows due to UNC paths
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.
Vulnerability Analysis
CVE-2024-43394 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.
Timeline
reported
Weakness Type
What is a SSRF Vulnerability?
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
CVE-2024-43394 has been classified to as a SSRF vulnerability or weakness.
Products Associated with CVE-2024-43394
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Affected Versions
Apache Software Foundation Apache HTTP Server:- Version 2.4.0, <= 2.4.63 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.