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HTTP ServerWeb server / proxy · Apache

CVE-2024-43394

HIGH · 7.5 CVSS v3.1 Published 2025-07-10
Fix available
A fix is available. Upgrade to 2.4.64 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

SSRF vulnerability in Apache HTTP Server on Windows allows attackers to leak NTLM hashes to malicious servers via mod_rewrite or Apache expressions that pass unvalidated user input to UNC paths. This enables remote attackers to capture Windows authentication credentials by tricking the server into connecting to attacker-controlled SMB resources.

MitigationUpdate Apache HTTP Server to the patched version and restrict UNC path access on Windows servers by limiting SMB connections to trusted hosts. Review mod_rewrite rules and Apache expressions for unvalidated input being used in request handling.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
HTTP ServerWeb server / proxy
Affected:>= 2.4.0, < 2.4.64

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Apache HTTP Server version
    Run 'httpd -v' or 'apachectl -v' from the Apache bin directory, or inspect the ServerTokens/Server header in HTTP responses
    Affected if Version is 2.4.0 through 2.4.63 inclusive (any version >= 2.4.0 and < 2.4.64)
  2. Verify Windows platform
    Confirm the Apache server is running on a Windows host (check OS via 'systeminfo' or 'winver')
    Affected if The server is running on Windows; this vulnerability does not affect non-Windows systems
  3. Inspect mod_rewrite rules for UNC path handling
    Review httpd.conf and included configuration files for RewriteRule directives that incorporate user-supplied input (such as %{QUERY_STRING}, %{HTTP_HOST}, or request URI segments) into paths that could become UNC paths (paths starting with \\ or referencing SMB shares)
    Affected if mod_rewrite rules exist that pass unvalidated user input to UNC-style paths without proper validation
  4. Check Apache expressions for SSRF vectors
    Search configuration files for expressions (using 'expr' in RewriteCond or other directives) that construct file or request paths from user input and could be directed to remote SMB resources
    Affected if Expressions in the configuration use raw user input to build paths without validation that prevents UNC path construction

You are affected if Apache HTTP Server versions 2.4.0 through 2.4.63 are running on Windows with mod_rewrite or Apache expressions that allow unvalidated user input to be used in UNC path contexts.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.4.64 or later
Fixed in 2.4.64
Interim mitigation

Update Apache HTTP Server to the patched version and restrict UNC path access on Windows servers by limiting SMB connections to trusted hosts. Review mod_rewrite rules and Apache expressions for unvalidated input being used in request handling.

Recommended fix High confidence

2.4.64

  1. 1. Back up your current Apache HTTP Server configuration files (httpd.conf and any included files) and document your current setup
  2. 2. Stop the Apache HTTP Server service
  3. 3. Download Apache HTTP Server version 2.4.64 from the official Apache download page (httpd.apache.org) or your distribution's package repository
  4. 4. Verify the integrity of the downloaded package using published checksums
  5. 5. Replace the existing Apache installation files with the new version 2.4.64
  6. 6. Restore your backed-up configuration files
  7. 7. Review and test your configuration syntax using 'httpd -t'
  8. 8. Start the Apache HTTP Server service
Caveat Review Apache HTTP Server 2.4.64 release notes for any changes that may affect your configuration or modules

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in HTTP Server Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,980
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-43394 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data