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Nextcloud ServerApplication · Nextcloud

CVE-2018-16465

MEDIUM · 5.3 CVSS v3.0 Published 2018-10-30
Fix available
A fix is available. Upgrade to 14.0.0 or later.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable Zero-click

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 · unedited
Missing state in Nextcloud Server prior to 14.0.0 would not enforce the use of a second factor at login if the the provider of the second factor failed to load.

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 confidence

Nextcloud Server prior to 14.0.0 contains a missing state validation in its two-factor authentication (2FA) mechanism. When the second factor provider fails to load during login, the system does not enforce the 2FA requirement, potentially allowing users to bypass second-factor authentication and gain access with only username and password.

MitigationUpgrade to Nextcloud Server 14.0.0 or later which includes proper state handling to enforce 2FA even when the provider fails to load.

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
Affected:< 14.0.0

CVSS 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
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed Nextcloud Server version
    Check the Nextcloud admin panel, the version file, or use the occ command: 'occ --version' to determine the exact version number
    Affected if The installed version is prior to 14.0.0 (e.g., 13.x.x or earlier)
  2. Confirm Two-Factor Authentication is enabled
    Navigate to the Nextcloud admin settings or check the user configuration to see if any 2FA provider has been enabled for users
    Affected if 2FA is enabled and the server version is below 14.0.0
  3. Verify the 2FA provider can load successfully
    Test the login flow with a user who has 2FA configured, or check the 2FA provider logs/status in the Nextcloud admin panel to see if any providers report failures during authentication
    Affected if The 2FA provider fails to load or initialize during login attempts while the server version is below 14.0.0

A Nextcloud Server installation is affected if it runs a version lower than 14.0.0 and has Two-Factor Authentication enabled, as the 2FA enforcement can be bypassed when the provider fails to load.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to 14.0.0 or later
Fixed in 14.0.0
Interim mitigation

Upgrade to Nextcloud Server 14.0.0 or later which includes proper state handling to enforce 2FA even when the provider fails to load.

Fix this in Nextcloud Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-16465 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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