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Debian LinuxOperating system · Debian

CVE-2011-1930

CRITICAL · 9.8 CVSS v3.1 Published 2019-11-14
Fix available
A fix is available. Upgrade to 1.5.25 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
In klibc 1.5.20 and 1.5.21, the DHCP options written by ipconfig to /tmp/net-$DEVICE.conf are not properly escaped. This may allow a remote attacker to send a specially crafted DHCP reply which could execute arbitrary code with the privileges of any process which sources DHCP options.

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

The ipconfig utility in klibc 1.5.20 and 1.5.21 writes DHCP options to /tmp/net-$DEVICE.conf without proper escaping of special characters. A remote attacker on the same network segment can send a malicious DHCP reply containing crafted options with shell metacharacters. When any process sources these DHCP options (e.g., via shell script inclusion), arbitrary code execution occurs with the privileges of that process.

MitigationUpgrade klibc to version 1.5.22 or later which contains the fix for proper DHCP option escaping. If upgrading is not immediately possible, ensure untrusted network segments cannot deliver DHCP responses to vulnerable systems.

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
Debian LinuxOperating system
Affected:= 8.0= 9.0= 10.0
KlibcApplication
Affected:< 1.5.25

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. Check if klibc is installed
    On Debian-based systems: dpkg -l | grep klibc. On RPM-based systems: rpm -q klibc
    Affected if klibc package is not installed means not affected; if installed, proceed to version check
  2. Determine installed klibc version
    Run: dpkg -l klibc 2>/dev/null | grep klibc (Debian) or rpm -q --queryformat '%{VERSION}-%{RELEASE}' klibc (RPM). Compare the version number to the affected ranges: Debian 8.0, 9.0, 10.0 and klibc versions below 1.5.25
    Affected if Installed version is 1.5.20, 1.5.21, or any version below 1.5.25 on Debian systems indicates vulnerability
  3. Verify ipconfig utility exists
    Run: which ipconfig or find /usr -name ipconfig 2>/dev/null
    Affected if ipconfig binary is present and klibc version is vulnerable indicates potential exposure
  4. Check for DHCP-created configuration files
    Run: ls -la /tmp/net-*.conf 2>/dev/null to list any DHCP configuration files written by ipconfig
    Affected if Files matching /tmp/net-*.conf exist, indicating the system has processed DHCP responses and created vulnerable configuration files
  5. Inspect script usage of DHCP config files
    Search for scripts that source /tmp/net- files: grep -r 'source.*net-' /etc /root 2>/dev/null or grep -r '\. /tmp/net-' /etc /root 2>/dev/null
    Affected if Any script sources or includes /tmp/net-*.conf files, which would trigger code execution if malicious DHCP options are present

The system is affected if klibc version is below 1.5.25 (or matches Debian 8.0/9.0/10.0), the ipconfig utility is present, and any process sources the DHCP configuration files in /tmp/net-*.conf.

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 1.5.25 or later
Fixed in 1.5.25
Interim mitigation

Upgrade klibc to version 1.5.22 or later which contains the fix for proper DHCP option escaping. If upgrading is not immediately possible, ensure untrusted network segments cannot deliver DHCP responses to vulnerable systems.

Recommended fix High confidence

klibc >= 1.5.25

  1. Check the current version of klibc installed: dpkg -l | grep klibc or rpm -q klibc
  2. Update the package repository metadata: apt-get update (Debian/Ubuntu) or yum check-update (RHEL/CentOS)
  3. Upgrade klibc to version 1.5.25 or later: apt-get install klibc (Debian) or yum update klibc (RHEL/CentOS)
  4. Verify the installed version meets the minimum requirement of 1.5.25: dpkg -l klibc or rpm -q klibc
  5. Reboot the system to ensure the new klibc library is loaded for all network operations
Caveat Minor - klibc is typically used during early boot; ensure adequate testing in a non-production environment before deploying widely

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

Fix this in Debian Linux Scoped from the published advisory
  • Consultation8.0 h
  • Implementation4.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,840
Get the upgrade done

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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-2011-1930 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