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FreeBSDOperating system

CVE-2006-6165

HIGH · 7.8 CVSS v3.1 Published 2006-11-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
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
ld.so in FreeBSD, NetBSD, and possibly other BSD distributions does not remove certain harmful environment variables, which allows local users to gain privileges by passing certain environment variables to loading processes. NOTE: this issue has been disputed by a third party, stating that it is the responsibility of the application to properly sanitize the environment

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 dynamic linker (ld.so) in FreeBSD and NetBSD fails to remove harmful environment variables (such as LD_PRELOAD, LD_LIBRARY_PATH) before executing setuid/setgid programs. This allows local attackers to inject arbitrary code execution by manipulating the process environment, leading to privilege escalation.

MitigationApply vendor patches for the affected BSD distributions or upgrade to versions where the dynamic linker properly sanitizes environment variables before loading executables.

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
FreeBSDOperating system
Affected:= 6.2
NetbsdOperating system
Affected:= 2.0.4

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 your FreeBSD or NetBSD version
    Run 'uname -a' or check /etc/os-release (if available) to determine the exact version of FreeBSD or NetBSD
    Affected if The version matches FreeBSD 6.2 or NetBSD 2.0.4 exactly, or falls within the = 6.2 or = 2.0.4 range as specified in the affected products
  2. Locate setuid binaries on the system
    Run 'find / -perm -4000 -type f 2>/dev/null' to find all setuid binaries, which are the potential targets for this vulnerability
    Affected if Any setuid binaries exist on the system and the OS version is affected
  3. Test dynamic linker environment variable handling
    Create a test shared library and attempt to execute a known setuid binary with LD_PRELOAD set (e.g., 'LD_PRELOAD=/path/to/test.so /usr/bin/some-setuid-binary'). Check if the library is loaded by examining the process or its behavior
    Affected if The LD_PRELOAD environment variable is honored by setuid programs, indicating the dynamic linker fails to sanitize it
  4. Check for LD_LIBRARY_PATH handling in setuid contexts
    Similar to above, test if LD_LIBRARY_PATH is respected by setuid binaries by setting it before executing a setuid program
    Affected if The LD_LIBRARY_PATH environment variable influences the execution of setuid programs, showing the vulnerability is present
  5. Verify dynamic linker patch status
    Check if system patches have been applied by reviewing system change logs, security advisories, or the dynamic linker binary version (check /libexec/ld-elf.so* or equivalent path)
    Affected if The system remains unpatched and the dynamic linker version matches the vulnerable release

A system is affected if it runs FreeBSD 6.2 or NetBSD 2.0.4 (or the specified version range) AND contains setuid/setgid binaries that honor LD_PRELOAD or LD_LIBRARY_PATH environment variables due to the dynamic linker failing to sanitize them before execution.

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 vendor patches for the affected BSD distributions or upgrade to versions where the dynamic linker properly sanitizes environment variables before loading executables.

Fix this in FreeBSD Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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Scan for this in your stack

Free · runs locally
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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-2006-6165 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