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Enterprise LinuxOperating system · Redhat

CVE-2017-12171

MEDIUM · 6.5 CVSS v3.0 Published 2018-07-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
74/100
Remediation priority · Elevated
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
A regression was found in the Red Hat Enterprise Linux 6.9 version of httpd 2.2.15-60, causing comments in the "Allow" and "Deny" configuration lines to be parsed incorrectly. A web administrator could unintentionally allow any client to access a restricted HTTP resource.

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

A parsing regression in Apache HTTP Server 2.2.15-60 on RHEL 6.9 causes comments within 'Allow' and 'Deny' directives to be mishandled, effectively bypassing intended access control restrictions and potentially allowing unauthorized clients to access protected resources.

MitigationApply the vendor-supplied patch to httpd or upgrade to a patched version; alternatively, remove comments from Allow/Deny directives or migrate to the 2.4+ 'Require' syntax for access control.

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
Enterprise LinuxOperating system
Affected:= 6.9
Enterprise Linux DesktopOperating system
Affected:= 6.0
Enterprise Linux ServerOperating system
Affected:= 6.0
Enterprise Linux WorkstationOperating system
Affected:= 6.0
HTTP ServerWeb server / proxy
Affected:= 2.2.15-60

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
Low
Integrity
Low
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/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. Verify Apache HTTP Server version
    Run 'httpd -v' or 'apachectl -v' to get the server version. Also check 'rpm -q httpd' for the package version.
    Affected if Version is 2.2.15-60 specifically on RHEL 6.x
  2. Verify RHEL version
    Run 'cat /etc/redhat-release' or 'cat /etc/os-release' to determine the RHEL release.
    Affected if Running RHEL 6.0 through 6.9 (the affected version range)
  3. Identify Allow and Deny directives with comments
    Search configuration files (httpd.conf, included conf files in /etc/httpd/conf.d/) for 'Allow' and 'Deny' directives that contain comments (text following '#'). Use: grep -r '^\s*Allow\s' /etc/httpd/ and grep -r '^\s*Deny\s' /etc/httpd/ and inspect each for inline comments.
    Affected if Allow or Deny directives contain comments within the directive line (after the directive but before the closing parenthesis or on the same line)
  4. Check for Order and Require directives
    Examine configuration files for 'Order' or 'Require' directives to identify which access control syntax is in use. The vulnerability affects the older 2.2 'Order/Allow/Deny' syntax, not the 2.4+ 'Require' syntax.
    Affected if Using Order, Allow, Deny directives (2.2 syntax) rather than Require (2.4+ syntax)

You are affected if running Apache 2.2.15-60 on RHEL 6.x with Allow/Deny directives that contain comments in the configuration, using the 2.2 access control syntax.

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

Apply the vendor-supplied patch to httpd or upgrade to a patched version; alternatively, remove comments from Allow/Deny directives or migrate to the 2.4+ 'Require' syntax for access control.

Fix this in Enterprise Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
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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-2017-12171 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