CVE-2026-55041
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 · uneditedHeap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
In the news
Third-party coverage- Microsoft July 2026 Patch Tuesday fixes massive 570 flaws, 3 zero-days
- Microsoft CVE Summary - Bleeping Computer
Surfaced from public web coverage — external links open in a new tab.
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 · low confidenceA heap-based buffer overflow vulnerability exists in Microsoft Office Excel that allows an attacker to execute arbitrary code locally on the affected system. The vulnerability stems from improper bounds checking when Excel processes certain data, leading to heap memory corruption.
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 dataall versions= 2016all versionsall versionsall versionsall versions< 16.0.10417.20175CVSS 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
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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 checksWork through these to decide whether this CVE applies to you.
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Verify Excel installationOpen File Explorer and navigate to the Office installation directory (typically C:\Program Files\Microsoft Office\root\Office16 or C:\Program Files (x86)\Microsoft Office\root\Office16) or check Program Files for Excel.exe. Alternatively, launch Excel and go to File > Account > About Excel.Affected if Excel.exe is not found on the system, meaning Excel is not installed.
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Determine installed Excel versionIn Excel, click File > Account > About Excel and note the version number shown (for example, 16.0.xxxxx.xxxxx). Or right-click Excel.exe in the installation folder, select Properties, and check the Details tab for the File version.Affected if The version displayed is any version of Microsoft 365 Apps, Excel 2016, Office 2019, Office 2021, Office 2024, or for Office Online Server the version is lower than 16.0.10417.20175.
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Check Excel process activityOpen Task Manager, look for running EXCEL.EXE processes under the Processes tab, or use command line: tasklist | findstr EXCEL.EXEAffected if Excel is actively running and processing files - the vulnerability triggers when Excel processes specially crafted data.
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Verify Office update statusOpen Excel, go to File > Account > Update Options and check when updates were last applied. In Windows Update (Settings > Update & Security > Windows Update), view update history for Microsoft Office security patches.Affected if Unable to confirm recent security updates have been applied, or updates are pending installation.
If Excel is installed and running any version other than a patched Office Online Server version 16.0.10417.20175 or higher, the environment falls within the affected product range and may be vulnerable.
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 data16.0.10417.20175
Apply the latest Microsoft security updates for Microsoft Office Excel as they become available. Until a patch is released, exercise caution when opening Excel files from untrusted sources and consider enabling Protected View for files from external sources.
- Consultation4.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-55041 — 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-2026-55041 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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