CVE-2016-3273
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 · uneditedThe XSS Filter in Microsoft Internet Explorer 9 through 11 and Microsoft Edge does not properly restrict JavaScript code, which allows remote attackers to obtain sensitive information via a crafted web site, aka "Microsoft Browser Information Disclosure 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 confidenceThe XSS Filter in Microsoft Internet Explorer 9-11 and Edge contains a flaw that allows JavaScript code to execute in contexts where it should be blocked. Attackers can craft malicious webpages that bypass the built-in XSS filter, enabling them to potentially steal sensitive information such as session tokens, cookies, or other data accessible via JavaScript.
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= 9= 10= 11CVSS 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
- High
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify Internet Explorer versionOpen Internet Explorer, click the gear icon (or press Alt), select About Internet Explorer. Note the version number shown (9, 10, or 11).Affected if Version is 9, 10, or 11 (note: version 9 shows as 9, version 10 shows as 10, version 11 shows as 11)
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Confirm if using Microsoft EdgeCheck if Microsoft Edge browser is in use. Open Edge and verify it launches successfully.Affected if Microsoft Edge is being used (all versions affected)
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Verify if security update KB3177358 is installedOpen Control Panel > Programs and Features > View installed updates. Search for 'KB3177358' in the list of installed updates.Affected if KB3177358 is NOT listed in installed updates (unpatched state)
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Check XSS filter status in Internet ExplorerOpen Internet Explorer, go to Internet Options > Security tab > Custom level. Scroll to 'Script ActiveX controls marked safe for scripting' and locate the 'Enable XSS filter' setting under the Miscellaneous section.Affected if XSS filter is set to Enable (vulnerability applies when filter is on; if disabled, the bypass cannot be exploited but browser has less protection)
A user is affected if they run unpatched Internet Explorer 9-11 or any version of Microsoft Edge with the XSS filter enabled, as the bypass allows scripts to execute in contexts the filter should block.
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 Microsoft security update KB3177358 (or subsequent relevant patches) to affected browsers. As defense-in-depth, implement Content Security Policy (CSP) headers on web applications to restrict inline script execution.
- Consultation1.0 h
- Implementation2.0 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-2016-3273 — 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-2016-3273 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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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.
- 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