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NVD / CVE Program· CNA hackerone

CVE-2016-9463: Nextcloud Server before 9.0.54 and 10.0.1 & ownCloud Server before 9.1.2, 9.0.6, and 8.2.9 suffer from SMB User Authentication Bypass.

HighCVSS 8.1 · v3.0—No exploit No fix recorded

Noroxi assessment

Priority: Monitor (action score 33/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 4% (FIRST EPSS); higher than 90.9% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • No fixed version is recorded, but the references include a patch (commit or PR) link.

Low priority for now. See the fix and affected versions sections below.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Nextcloud Server before 9.0.54 and 10.0.1 & ownCloud Server before 9.1.2, 9.0.6, and 8.2.9 suffer from SMB User Authentication Bypass. Nextcloud/ownCloud include an optional and not by default enabled SMB authentication component that allows authenticating users against an SMB server. This backend is implemented in a way that tries to connect to a SMB server and if that succeeded consider the user logged-in. The backend did not properly take into account SMB servers that have any kind of anonymous auth configured. This is the default on SMB servers nowadays and allows an unauthenticated attacker to gain access to an account without valid credentials. Note: The SMB backend is disabled by default and requires manual configuration in the Nextcloud/ownCloud config file. If you have not configured the SMB backend then you're not affected by this vulnerability.

Published
Mar 27, 2017
Updated
Jun 16, 2026
EPSS
4.0% · 90th percentile

Report tools

JSON

Action score

33

Monitor

Low priority for now.

CVSS
32 / 40 · 8.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 4.0%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
nextcloudnextcloud server
owncloudowncloud

Versions reported by the vendor

Affected version ranges reported by the assigning authority (hackerone). Independent of NVD's CPE analysis and usually ahead of it.

  • n/a Nextcloud Server & ownCloud Server Nextcloud Server before 9.0.54 and 10.0.1 & ownCloud Server before 9.1.2, 9.0.6, and 8.2.9

    • Nextcloud Server & ownCloud Server Nextcloud Server before 9.0.54 and 10.0.1 & ownCloud Server before 9.1.2, 9.0.6, and 8.2.9affected
Affected versions · NVD (5)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • nextcloud nextcloud serverbefore 9.0.54
  • nextcloud nextcloud server10.0.0 and later · before 10.0.1
  • owncloud owncloud8.2.0 and later · before 8.2.9
  • owncloud owncloud9.0.0 and later · before 9.0.4
  • owncloud owncloud9.1.0 and later · before 9.1.2

Same product

nextcloud: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-26482Scope of workflow operations is not validated in nextcloud server
    40Plan
  • CVE-2021-32802Preview generation used third-party library not suited for user-generated content in Nextcloud server
    40Plan
  • CVE-2021-32726Webauthn tokens not removed after user has been deleted
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2016-9461Mar 27, 2017 · Nextcloud Server before 9.0.52 & ownCloud Server before 9.0.4 are not properly verifying edit check permissions on WebDAV copy actions.
    18Monitor
  • ← EarlierCVE-2016-9462Mar 27, 2017 · Nextcloud Server before 9.0.52 & ownCloud Server before 9.0.4 are not properly verifying restore privileges when restoring a file.
    18Monitor
  • Later →CVE-2016-9464Mar 27, 2017 · Nextcloud Server before 9.0.54 and 10.0.0 suffers from an improper authorization check on removing shares.
    17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Not on record for this CVE: EPSS history · researcher credit · variant or chain candidate.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-303 · Incorrect Implementation of Authentication Algorithm

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records