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FreeBSDOperating system

CVE-1999-0040

HIGH · 7.2 CVSS v2.0 Published 1997-05-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
77/100
Remediation priority · High
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
Buffer overflow in Xt library of X Windowing System allows local users to execute commands with root privileges.

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

Buffer overflow vulnerability in the Xt library of the X Window System allows local unprivileged users to execute arbitrary commands with root privileges through malformed input handling.

MitigationApply vendor patches or upgrade to a patched version of the X Window System/Xt library; restrict local access to trusted users until patched.

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:= 1.1.5.1= 2.0
IrixOperating system
Affected:= 4.0= 5.0= 5.3= 6.0= 6.1= 6.2= 6.3= 6.4
Bsd OsOperating system
Affected:= 2.0= 2.0.1= 2.1
Hp UxOperating system
Affected:= 9.00= 9.01= 9.10= 10.00= 10.01= 10.08= 10.09= 10.10= 10.16= 10.20= 10.24= 10.30
AixOperating system
Affected:= 3.2= 4.1= 4.2
Asl Ux 4800Operating system
Affected:= 64
Ews Ux VOperating system
Affected:= 4.2= 4.2mp
Up Ux VOperating system
Affected:= 4.2mp

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
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:L/AC:L/Au:N/C:C/I:C/A:C

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 if X Window System is installed
    Run 'which X' or 'which Xt' or check for /usr/X11* or /usr/lib/X11* directories
    Affected if X Window System is not installed then the system is not affected
  2. Determine the Xt library version
    Check the Xt library file version: 'ls -la /usr/lib/libXt*' or use 'strings' on libXt.so to find version strings, or check the X11 version with 'X -version'
    Affected if The installed Xt library version matches one of the affected versions listed (FreeBSD 1.1.5.1/2.0, Irix 4.0-6.4, BSDi 2.0-2.1, HP-UX 9.00-10.30, AIX 3.2-4.2, NEC variants)
  3. Confirm the operating system version
    Run 'uname -a' or 'oslevel' (AIX) or 'swlist' (HP-UX) to get the exact OS version
    Affected if The OS version matches any of the affected versions listed in the CVE
  4. Check for presence of local unprivileged user accounts
    Review /etc/passwd for non-root users, or run 'id' to see current user privileges
    Affected if The system has local unprivileged user accounts that could exploit this local privilege escalation vulnerability

A system is affected if it runs one of the listed OS versions with the X Window System/Xt library installed and has untrusted local users able to access the Xt input handling code.

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 or upgrade to a patched version of the X Window System/Xt library; restrict local access to trusted users until patched.

Fix this in FreeBSD Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing6.0 h
  • Review / QA3.0 h
18.0 hours of engineering $3,120
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Scan for this in your stack

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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-1999-0040 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