CVE-2016-4026
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 · uneditedAn issue was discovered in Open-Xchange OX App Suite before 7.8.1-rev11. The content sanitizer component has an issue with filtering malicious content in case invalid HTML code is provided. In such cases the filter will output a unsanitized representation of the content. Malicious script code can be executed within a user's context. This can lead to session hijacking or triggering unwanted actions via the web interface (sending mail, deleting data etc.). Attackers can use this issue for filter evasion to inject script code later on.
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 confidenceCross-site scripting (XSS) vulnerability in Open-Xchange OX App Suite's content sanitizer. When invalid HTML is provided to the sanitizer, it outputs unsanitized content instead of properly filtering it, allowing attackers to inject malicious script code that executes in user sessions.
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<= 7.8.1CVSS 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
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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 OX App Suite versionLocate the installed OX App Suite version by checking the package manager, installation directory, or administration interface for the OX Appsuite version numberAffected if The installed version is 7.8.1 or any version prior to 7.8.1-rev11
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Determine if content sanitizer is in useReview the OX App Suite configuration to confirm whether the content sanitizer is enabled for HTML content processing, typically found in email or document handling settingsAffected if The content sanitizer module is active and processing HTML input from users
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Check for recent security patchesExamine the installed patches or hotfixes applied to OX App Suite for any references to CVE-2016-4026 or content sanitizer fixesAffected if No patches addressing CVE-2016-4026 have been applied
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Review input handling configurationInspect the content sanitizer configuration files or admin settings to verify how invalid HTML is handled during processingAffected if The sanitizer is configured to output content on invalid HTML rather than reject or sanitize it
A user is affected if OX App Suite version 7.8.1 or earlier is installed and the content sanitizer is processing HTML input without the CVE-2016-4026 patch applied.
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 to OX App Suite version 7.8.1-rev11 or later which contains the corrected content sanitizer. Alternatively, implement additional input validation layers before content reaches the sanitizer.
- Consultation3.0 h
- Implementation6.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-4026 — 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-2016-4026 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
- No spam, self-promotion, credentials, or personal data