Nextcloud ServerApplication · Nextcloud
CVE-2017-0893
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 · uneditedNextcloud Server before 9.0.58 and 10.0.5 and 11.0.3 are shipping a vulnerable JavaScript library for sanitizing untrusted user-input which suffered from a XSS vulnerability caused by a behaviour change in Safari 10.1 and 10.2. Note that Nextcloud employs a strict Content-Security-Policy preventing exploitation of this XSS issue on modern web browsers.
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 confidenceNextcloud Server shipped a vulnerable JavaScript library for sanitizing user input that contained an XSS vulnerability. The flaw was triggered by a behavior change in Safari 10.1 and 10.2, which allowed malicious scripts to bypass the sanitization. However, Nextcloud's strict Content-Security-Policy prevents exploitation on modern web browsers.
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
Nextcloud ServerApplication
< 9.0.58>= 10.0.0, < 10.0.5>= 11.0.0, < 11.0.3CVSS 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
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:L/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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Check installed Nextcloud Server versionLocate and read the version file in your Nextcloud installation directory, or run 'occ --version' from the Nextcloud root directory if occ is availableAffected if The version number is less than 9.0.58, or between 10.0.0 and 10.0.5 (exclusive), or between 11.0.0 and 11.0.3 (exclusive)
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Verify Content-Security-Policy header configurationCheck your web server configuration (Apache/Nginx) or Nextcloud config.php for ' CSP' or 'contentsecuritypolicy' settingsAffected if The CSP header is disabled or overly permissive (not set to Nextcloud's strict default)
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Identify if Safari 10.1 or 10.2 is in useThis cannot be reliably detected server-side; consult your user base or web server access logs for Safari versionsAffected if Users are accessing the Nextcloud instance primarily from Safari versions 10.1 or 10.2
You are affected if your Nextcloud Server version falls within the vulnerable ranges (< 9.0.58, 10.0.0-10.0.4, or 11.0.0-11.0.2) and your Content-Security-Policy is disabled, combined with Safari 10.1/10.2 clients accessing the server.
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 data9.0.5810.0.511.0.3
Update Nextcloud Server to version 9.0.58, 10.0.5, or 11.0.3 or later to obtain the patched sanitization library. The existing CSP provides additional defense-in-depth protection.
Fix this in Nextcloud Server
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-0893 — 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-2017-0893 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