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ExcelApplication · Microsoft

CVE-2016-3279

MEDIUM · 5.5 CVSS v3.0 Published 2016-07-13
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
Remediation priority · Elevated
No privileges

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
Microsoft Office 2010 SP2, Excel 2010 SP2, PowerPoint 2010 SP2, Word 2010 SP2, Excel 2013 SP1, PowerPoint 2013 SP1, Word 2013 SP1, Excel 2013 RT SP1, PowerPoint 2013 RT SP1, Word 2013 RT SP1, Excel 2016, Word 2016, Word Automation Services on SharePoint Server 2010 SP2, and Office Web Apps 2010 SP2 allow remote attackers to execute arbitrary code via a crafted XLA file, aka "Microsoft Office Remote Code Execution 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 confidence

A remote code execution vulnerability in Microsoft Office products (2010, 2013, 2016) and Office Web Apps allows arbitrary code execution via specially crafted XLA (Excel Add-in) files. When a user opens a malicious XLA file, the attacker can run code in the context of the current user.

MitigationApply Microsoft security updates for CVE-2016-3279 to all affected Office installations. Additionally, configure email/gateway filtering to block XLA attachments and disable XLA add-in loading in the Trust Center settings until patches are deployed.

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
ExcelApplication
Affected:= 2010= 2013= 2016
Excel RtApplication
Affected:= 2013
OfficeApplication
Affected:= 2010
Office Web AppsApplication
Affected:= 2010
PowerpointApplication
Affected:= 2010= 2013
Powerpoint RtApplication
Affected:= 2013
Sharepoint ServerApplication
Affected:= 2010
WordApplication
Affected:= 2010= 2013= 2016

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
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

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 installed Microsoft Office product and version
    Open any Office application (Excel, Word, PowerPoint), go to File > Account, and note the version shown under 'About [App]'. Alternatively, open Programs and Features in Control Panel and locate Microsoft Office in the list.
    Affected if The installed version is Excel, PowerPoint, or Word 2010, 2013, or 2016 (or the corresponding Office suite version)
  2. Confirm XLA add-in support exists in the installation
    In the affected Office application, navigate to File > Options > Trust Center > Trust Center Settings > Add-ins. Look for 'Excel Add-ins' or 'PowerPoint Add-ins' listed as active add-in types.
    Affected if XLA add-in types are available and listed in the Add-ins management interface
  3. Determine if XLA add-ins are allowed to load
    In Trust Center Settings > Add-ins, check whether the option to disable all Application Add-ins is unchecked (meaning add-ins are enabled). Also verify no group policy is blocking add-ins.
    Affected if Add-ins are not disabled and XLA files can be loaded by the application
  4. Check for presence of security update for this CVE
    Open Windows Update, view Update History, or check the installed updates list for a security update released around July 2016 that addresses this vulnerability in Office.
    Affected if The specific security update for CVE-2016-3279 is NOT installed (the system is unpatched)
  5. Verify XLA file attachment handling in email gateway
    Inspect email security gateway or mail server configuration to determine if XLA file attachments are being blocked or filtered before delivery.
    Affected if XLA attachments are not being blocked and could reach end-user mailboxes

A user is affected if they have an unpatched Office 2010/2013/2016 installation where XLA add-ins are permitted to load, allowing malicious XLA files to execute code upon opening.

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 Microsoft security updates for CVE-2016-3279 to all affected Office installations. Additionally, configure email/gateway filtering to block XLA attachments and disable XLA add-in loading in the Trust Center settings until patches are deployed.

Fix this in Excel Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2016-3279 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