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HTTP ServerWeb server / proxy · Apache

CVE-2018-8011

HIGH · 7.5 CVSS v3.0 Published 2018-07-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
High EPSS 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
By specially crafting HTTP requests, the mod_md challenge handler would dereference a NULL pointer and cause the child process to segfault. This could be used to DoS the server. Fixed in Apache HTTP Server 2.4.34 (Affected 2.4.33).

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

In Apache HTTP Server 2.4.33, the mod_md (mod_md challenge handler) module contains a NULL pointer dereference vulnerability. By sending specially crafted HTTP requests, an attacker can trigger the handler to dereference a NULL pointer, causing the child process to crash with a segmentation fault.

MitigationUpgrade Apache HTTP Server to version 2.4.34 or later to patch the NULL pointer dereference in mod_md.

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:= 2.4.33
Cloud BackupApplication
Affected:all versions

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
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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. Identify the Apache HTTP Server version
    Run 'httpd -v' or 'apache2 -v' to display the installed version
    Affected if The installed version is exactly 2.4.33
  2. Determine if mod_md module is enabled
    Check the configuration file (httpd.conf or conf.modules.d) for 'LoadModule md_module' or run 'httpd -M' to list loaded modules
    Affected if mod_md module is loaded/enabled in the configuration
  3. Verify the attack surface
    Review server configuration to confirm mod_md handles HTTP requests (check for 'MDomain' directives in the config)
    Affected if mod_md is actively configured with MDomain directives handling requests
  4. Check for NetApp Cloud Backup installation
    Identify if the Apache HTTP Server instance is part of NetApp Cloud Backup product by checking installed packages or product metadata
    Affected if The Apache HTTP Server is bundled as part of NetApp Cloud Backup (all versions are affected regardless of Apache version)

A system is affected if it runs Apache HTTP Server version 2.4.33 with mod_md module enabled, or if it runs any version of NetApp Cloud Backup that includes the vulnerable Apache component.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Apache HTTP Server to version 2.4.34 or later to patch the NULL pointer dereference in mod_md.

Fix this in HTTP Server Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
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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-2018-8011 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