CVE-2016-0028
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 · uneditedOutlook Web Access (OWA) in Microsoft Exchange Server 2013 SP1, Cumulative Update 11, and Cumulative Update 12 and 2016 Gold and Cumulative Update 1 does not properly restrict loading of IMG elements, which makes it easier for remote attackers to track users via a crafted HTML e-mail message, aka "Microsoft Exchange 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 confidenceOutlook Web Access in Microsoft Exchange Server 2013 and 2016 fails to properly restrict loading of IMG elements in HTML emails. Attackers can embed crafted external image references in phishing emails that, when rendered by OWA, leak user information such as IP addresses, email access times, and client details to the attacker's controlled server.
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 versionsCVSS 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
- None
- Availability
- None
CVSS:3.0/AV:L/AC:L/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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Verify OWA is accessibleConfirm Outlook Web Access is exposed by checking IIS sites or testing access to /owa virtual directory on the Exchange serverAffected if OWA is accessible externally or internally to users
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Identify Exchange Server versionRun Get-ExchangeServer | Select Name,AdminDisplayVersion or check Exchange setup log for version number (15.0 = Exchange 2013, 15.1 = Exchange 2016)Affected if Version is Exchange Server 2013 or 2016 (builds 15.0.x or 15.1.x)
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Confirm external image loading is not blockedCheck OWA mailbox policy settings: Get-OwaMailboxPolicy | Select-Object Name,DirectFileAccessOn*,*Image* or review Exchange admin center > mail flow rules for rules that strip external image URLsAffected if External image loading is permitted in OWA policies (DirectFileAccessToSecondNavigationLevelEnabled and other related parameters are not explicitly disabled)
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Inspect HTML email rendering behaviorSend a test HTML email containing an <img> tag with external src to a test OWA mailbox, then capture network traffic or check access logs on the external server for incoming requestsAffected if Requests from OWA servers appear in external server logs, confirming images load automatically without user interaction
User is affected if running Exchange Server 2013 or 2016 with OWA enabled and external image loading is not blocked in OWA mailbox policies
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 updates (MS16-010) to the affected Exchange Server versions. As a compensating control, configure OWA to block external image loading or implement Exchange transport rules to strip external image references from incoming emails.
- Consultation2.0 h
- Implementation3.0 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-2016-0028 — 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-2016-0028 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