CVE-1999-1055
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 · uneditedMicrosoft Excel 97 does not warn the user before executing worksheet functions, which could allow attackers to execute arbitrary commands by using the CALL function to execute a malicious DLL, aka the Excel "CALL Vulnerability."
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 confidenceMicrosoft Excel 97 fails to warn users before executing worksheet functions, enabling the CALL function to load and execute arbitrary DLLs, allowing remote attackers to run commands with the privileges of the user opening the spreadsheet.
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= 97CVSS 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
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/Au:N/C:P/I:P/A:P
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 installed Microsoft Excel versionOpen Excel, go to Help > About Microsoft Excel, or check Add/Remove Programs for Microsoft Excel 97. Alternatively, check the registry key HKEY_CLASSES_ROOT\Excel.Application\CurVer or look for EXCEL.EXE in Program Files and view its properties.Affected if The version displayed is exactly Excel 97 or the file version shows 8.0
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Verify the specific Excel 97 executableLocate the Excel executable (typically in C:\Program Files\Microsoft Office\Office or C:\Program Files\Microsoft Office\97) and check the file version property. Excel 97 executable version should be 8.0.xxxx.Affected if The executable version is 8.0.xxxx indicating Excel 97
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Confirm worksheet function execution behaviorCreate a test spreadsheet with a CALL function (e.g., =CALL("kernel32","GetVersion","")) and observe whether Excel executes it without displaying any security warning or prompting the user. In Excel 97, this executes silently by design.Affected if The CALL function executes without any warning dialog appearing and the system executes the DLL call
The environment is affected if Microsoft Excel version 8.0 (Excel 97) is installed and the CALL worksheet function executes without triggering any security warnings.
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 dataUpgrade from Excel 97 to a currently supported Microsoft Excel version; disable macro execution and exercise extreme caution with spreadsheets from untrusted sources.
- Consultation2.0 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-1999-1055 — 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-1999-1055 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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