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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (4.09%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.0
- 8.1 HIGHCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 4.09% probability · 91th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-303, CWE-287
- Affected
- nextcloud/nextcloud server · owncloud/owncloud
- Source
- support@hackerone.com
EPSS 4.1% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/nextcloud/apps/commit/b85ace6840b8a6704641086bc3b8eb8e81cb2274Issue Tracking, Patch, Third Party Advisory
- https://github.com/nextcloud/apps/commit/decb91fd31f4ffab191cbf09ce4e5c55c67a4087Issue Tracking, Patch, Third Party Advisory
- https://github.com/owncloud/apps/commit/16cbccfc946c8711721fa684d78135ca1fb64791Issue Tracking, Patch, Third Party Advisory
- https://github.com/owncloud/apps/commit/5d47e7b52646cf79edadd78ce10c754290cbb732Issue Tracking, Patch, Third Party Advisory
- https://github.com/owncloud/apps/commit/a0e07b7ddd5a5fd850a6e07f8457d05b76a300b3Issue Tracking, Patch, Third Party Advisory
- https://hackerone.com/reports/148151Exploit, Third Party Advisory
- https://nextcloud.com/security/advisory/?id=nc-sa-2016-006Patch, Vendor Advisory
- https://owncloud.org/security/advisory/?id=oc-sa-2016-017Patch, Vendor Advisory
- https://rhinosecuritylabs.com/2016/10/operation-ownedcloud-exploitation-post-exploitation-persistence/Exploit, Technical Description, Third Party Advisory
- https://github.com/nextcloud/apps/commit/b85ace6840b8a6704641086bc3b8eb8e81cb2274Issue Tracking, Patch, Third Party Advisory
- https://github.com/nextcloud/apps/commit/decb91fd31f4ffab191cbf09ce4e5c55c67a4087Issue Tracking, Patch, Third Party Advisory
- https://github.com/owncloud/apps/commit/16cbccfc946c8711721fa684d78135ca1fb64791Issue Tracking, Patch, Third Party Advisory
- https://github.com/owncloud/apps/commit/5d47e7b52646cf79edadd78ce10c754290cbb732Issue Tracking, Patch, Third Party Advisory
- https://github.com/owncloud/apps/commit/a0e07b7ddd5a5fd850a6e07f8457d05b76a300b3Issue Tracking, Patch, Third Party Advisory
- https://hackerone.com/reports/148151Exploit, Third Party Advisory
- https://nextcloud.com/security/advisory/?id=nc-sa-2016-006Patch, Vendor Advisory
- https://owncloud.org/security/advisory/?id=oc-sa-2016-017Patch, Vendor Advisory
- https://rhinosecuritylabs.com/2016/10/operation-ownedcloud-exploitation-post-exploitation-persistence/Exploit, Technical Description, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.