dbcve.org
HTTP ServerWeb server / proxy · Apache

CVE-2025-59775

HIGH · 7.5 CVSS v3.1 Published 2025-12-05
Fix available
A fix is available. Upgrade to 2.4.66 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) vulnerability  in Apache HTTP Server on Windows with AllowEncodedSlashes On and MergeSlashes Off  allows to potentially leak NTLM hashes to a malicious server via SSRF and malicious requests or content Users are recommended to upgrade to version 2.4.66, which fixes the issue.

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 · moderate confidence

Apache HTTP Server on Windows with AllowEncodedSlashes enabled and MergeSlashes disabled contains an SSRF vulnerability that can leak NTLM hashes to attacker-controlled servers via specially crafted requests. The vulnerability stems from how Apache handles encoded slashes in URLs on Windows, allowing malicious requests to trigger outbound connections that transmit NTLM authentication credentials.

MitigationUpgrade to Apache HTTP Server version 2.4.66, or alternatively disable AllowEncodedSlashes or enable MergeSlashes in the configuration to remediate this vulnerability.

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, < 2.4.66

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 the operating system
    Determine if the Apache server is running on Windows. Review server environment, Apache error/access logs for Windows paths, or run 'systeminfo' on the host to confirm the OS.
    Affected if The server is running on a non-Windows OS - the vulnerability only applies to Windows environments.
  2. Check the Apache version
    Run 'httpd -v' (or 'apache2 -v') to obtain the installed Apache HTTP Server version number.
    Affected if The installed version is >= 2.4.0 and < 2.4.66 - versions within this range are affected.
  3. Locate the Apache configuration file
    Find the main Apache configuration file (httpd.conf or apache2.conf). Common locations include conf/httpd.conf, /etc/apache2/apache2.conf, or C:\Program Files\Apache Software Foundation\Apache2.4\conf\httpd.conf on Windows.
    Affected if This step enables reading the configuration directives needed for subsequent checks.
  4. Check if AllowEncodedSlashes is enabled
    Search the configuration file for the AllowEncodedSlashes directive. Run 'grep -i AllowEncodedSlashes httpd.conf' or manually inspect the config file.
    Affected if AllowEncodedSlashes is set to On - when enabled (especially with URLs containing encoded slashes like %2F), the vulnerability can be triggered.
  5. Check if MergeSlashes is disabled
    Search the configuration file for the MergeSlashes directive. Run 'grep -i MergeSlashes httpd.conf' or manually inspect the config file.
    Affected if MergeSlashes is not explicitly set to On (defaults to Off). When MergeSlashes is Off, Apache does not merge consecutive slashes, which is required for the exploit.

A Windows server running Apache 2.4.0 to 2.4.65 with AllowEncodedSlashes enabled and MergeSlashes disabled is affected by this vulnerability.

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 2.4.66 or later
Fixed in 2.4.66
Interim mitigation

Upgrade to Apache HTTP Server version 2.4.66, or alternatively disable AllowEncodedSlashes or enable MergeSlashes in the configuration to remediate this vulnerability.

Recommended fix High confidence

2.4.66

  1. 1. Back up your current Apache HTTP Server configuration files (httpd.conf and included files)
  2. 2. Download Apache HTTP Server version 2.4.66 from the official Apache download site (httpd.apache.org)
  3. 3. Stop the Apache HTTP Server service
  4. 4. Install or upgrade to Apache HTTP Server 2.4.66
  5. 5. Restore your backed-up configuration files
  6. 6. Start the Apache HTTP Server service
  7. 7. Verify the server is running correctly and check error logs for any issues

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

Fix this in HTTP Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,090
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,744.

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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-2025-59775 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