CVE-1999-0839
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 · uneditedWindows NT Task Scheduler installed with Internet Explorer 5 allows a user to gain privileges by modifying the job after it has been scheduled.
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 confidenceWindows NT Task Scheduler installed with Internet Explorer 5 contains a privilege escalation vulnerability where scheduled jobs can be modified by users after scheduling. This allows a local attacker to alter job properties (such as the executable path or parameters) to run with elevated privileges, gaining unauthorized system access.
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= 5= 5.0CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify Internet Explorer versionCheck the installed Internet Explorer version by examining the registry key HKLM\SOFTWARE\Microsoft\Internet Explorer or via the About dialog in IE. Look for version 5.0 specifically.Affected if Internet Explorer version 5.0 is installed on Windows NT
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Verify Task Scheduler is presentCheck for the presence of the Task Scheduler service (schedsvc.dll) and the scheduled tasks folder typically at %systemroot%\Tasks or via the 'at' command output.Affected if Task Scheduler is installed and accessible on the system
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Enumerate existing scheduled jobsList all scheduled tasks using the 'at' command or by inspecting the Task Scheduler folder. Note which jobs run with elevated (SYSTEM or administrator) privileges.Affected if Any scheduled jobs exist that run with elevated privileges
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Inspect ACLs on scheduled tasksReview the security descriptor (DACL) of each scheduled task to determine if non-privileged users have Write or WriteOwner permissions that would allow modifying job properties such as the executable path or parameters.Affected if Non-administrator users have permissions to modify scheduled job properties
The system is affected if Internet Explorer 5.0 is installed alongside Task Scheduler and any scheduled jobs have misconfigured permissions allowing standard users to modify job properties that execute with elevated privileges.
Generated from the published advisory. Verify against your own configuration.
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 dataApply vendor patches for this vulnerability. For legacy systems no longer supported, migrate to modern Windows versions and remove Internet Explorer 5. Ensure Task Scheduler jobs have proper ACLs preventing unauthorized modification.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-1999-0839 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-1999-0839 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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