Nextcloud ServerApplication · Nextcloud
CVE-2018-3776
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 · uneditedImproper input validator in Nextcloud Server prior to 12.0.3 and 11.0.5 could lead to an attacker's actions not being logged in the audit log.
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 confidenceThis is an improper input validation vulnerability in Nextcloud Server that allows attackers to perform actions that bypass audit logging. The input validation failure means certain user activities are not recorded in the audit log, compromising the integrity of security monitoring and forensic capabilities.
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
>= 11.0.0, < 11.0.5>= 12.0.0, < 12.0.3CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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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Determine installed Nextcloud Server versionCheck the version.php file in the Nextcloud root directory, or run 'occ --version' from the Nextcloud directory if occ is available, or log into the Nextcloud admin interface and check the administration overview page.Affected if The installed version falls within 11.0.0 to 11.0.4 inclusive, or 12.0.0 to 12.0.2 inclusive.
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Confirm audit logging app is enabledLog into Nextcloud as an administrator, navigate to Apps, and verify that the 'Audit' app (or 'Logging' app depending on version) is enabled. Alternatively, check the config/config.php file for 'audit' in the appsenabled array.Affected if The audit logging app is enabled and the version is vulnerable as checked above.
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Verify audit log is recording user activitiesAccess the audit log through the Nextcloud admin interface under Logging or by reviewing the data/audit.log file (location may vary based on configuration). Attempt a test action such as creating or deleting a file, then check if that action appears in the audit log.Affected if Test actions are NOT recorded in the audit log despite the audit app being enabled, indicating the input validation bypass is present.
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Check for recent audit log gapsReview the audit log file or interface for the time period corresponding to the vulnerability window. Look for missing entries that should normally be recorded, such as file operations, login/logout events, or admin actions.Affected if There are noticeable gaps in the audit log where expected security events are missing.
A user is affected if their Nextcloud Server version is 11.0.0-11.0.4 or 12.0.0-12.0.2 AND the audit logging app is enabled but fails to record activities.
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 data11.0.512.0.3
Update Nextcloud Server to version 12.0.3 or 11.0.5 or later to patch the input validation flaw and restore proper audit logging functionality.
Fix this in Nextcloud Server
Scoped from the published advisory
- Consultation1.0 h
- Implementation3.0 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 $1,952.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-3776 — 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-2018-3776 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
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