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Dhcp6cApplication · Linux

CVE-2011-2717

CRITICAL · 9.8 CVSS v3.1 Published 2019-11-27
Fix available
A fix is available. Upgrade to after 2011-07-25 or later.
See remediation →
100/100
Remediation priority · Urgent
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
The DHCPv6 client (dhcp6c) as used in the dhcpv6 project through 2011-07-25 allows remote DHCP servers to execute arbitrary commands via shell metacharacters in a hostname obtained from a DHCP message.

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

The dhcp6c DHCPv6 client fails to sanitize hostname values received from remote DHCP servers, allowing injection of arbitrary shell commands through metacharacters in the hostname field. When the client processes a malicious hostname containing shell metacharacters (such as ;, |, or $()), it can lead to remote command execution on the client system.

MitigationImplement strict input validation on hostname fields received from DHCP messages, removing or escaping shell metacharacters before use. Alternatively, avoid passing hostname data to shell commands entirely by using safer API calls.

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
Dhcp6cApplication
Affected:<= 2011-07-25
Enterprise LinuxOperating system
Affected:= 4.0= 5.0

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
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 if dhcp6c is installed
    Check for the dhcp6c binary or package on the system using commands such as 'which dhcp6c', 'rpm -qa | grep dhcp', or 'dpkg -l | grep dhcp6'
    Affected if dhcp6c package is present on the system
  2. Determine dhcp6c version
    Run 'dhcp6c -v' or check the package version via the system package manager. Compare the build date or version number to the 2011-07-25 threshold
    Affected if The dhcp6c version or build date is on or before 2011-07-25
  3. Check Red Hat Enterprise Linux version
    If using RHEL, run 'cat /etc/redhat-release' or 'rpm -q redhat-release' to identify the exact version
    Affected if The system runs RHEL 4.0 or RHEL 5.0 with dhcp6c enabled
  4. Verify DHCPv6 client configuration is active
    Inspect dhcp6c configuration files typically located in /etc/dhcp6c.conf or /etc/dhcp6c/ and check if the service is running via 'ps aux | grep dhcp6c'
    Affected if dhcp6c is actively running or configured to start on boot
  5. Confirm hostname processing from DHCPv6
    Review the dhcp6c configuration for statements that process or use the hostname option received from DHCPv6 servers, such as 'send host-name' or similar hostname-related directives
    Affected if The configuration processes hostname values received from DHCPv6 servers and passes them to shell commands or scripts

The environment is affected if dhcp6c is installed and configured to process hostname values from DHCPv6 servers, with a version or system release matching the affected ranges (pre-July 2011 build or RHEL 4.0/5.0).

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 a release after 2011-07-25
Interim mitigation

Implement strict input validation on hostname fields received from DHCP messages, removing or escaping shell metacharacters before use. Alternatively, avoid passing hostname data to shell commands entirely by using safer API calls.

Recommended fix Moderate confidence

Red Hat Enterprise Linux 4.0/5.0 via respective RHSA patch; upstream dhcp project fixed after 2011-07-25

  1. Check the Red Hat Security Advisory (RHSA) for CVE-2011-2717 for your specific RHEL version (4.0 or 5.0)
  2. Run 'yum update dhcp' or 'yum update dhcpv6-client' to apply the security patch
  3. Verify the update was successful by checking the installed version with 'rpm -q dhcp' or 'rpm -q dhcpv6-client'
  4. Restart any dhcp6c services if they are running
Caveat Standard minor/patch update with no expected breaking changes for this security fix

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

Fix this in Dhcp6c Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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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-2011-2717 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