Vulnerability Name:

CVE-2021-32655 (CCN-202908)

Assigned:2021-06-01
Published:2021-06-01
Updated:2022-10-26
Summary:Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.11, 20.0.10, and 21.0.2, an attacker is able to convert a Files Drop link to a federated share. This causes an issue on the UI side of the sharing user. When the sharing user opens the sharing panel and tries to remove the "Create" privileges of this unexpected share, Nextcloud server would silently grant the share read privileges. The vulnerability is patched in versions 19.0.11, 20.0.10 and 21.0.2. No workarounds are known to exist.
CVSS v3 Severity:3.5 Low (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N)
3.1 Low (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): Required
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): Low
Integrity (I): None
Availibility (A): None
3.5 Low (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N)
3.1 Low (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): Required
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): Low
Integrity (I): None
Availibility (A): None
CVSS v2 Severity:3.5 Low (CVSS v2 Vector: AV:N/AC:M/Au:S/C:P/I:N/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Medium
Authentication (Au): Single_Instance
Impact Metrics:Confidentiality (C): Partial
Integrity (I): None
Availibility (A): None
4.0 Medium (CCN CVSS v2 Vector: AV:N/AC:L/Au:S/C:P/I:N/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): Single_Instance
Impact Metrics:Confidentiality (C): Partial
Integrity (I): None
Availibility (A): None
Vulnerability Type:CWE-Other
Vulnerability Consequences:Bypass Security
References:Source: MITRE
Type: CNA
CVE-2021-32655

Source: XF
Type: UNKNOWN
nextcloud-cve202132655-sec-bypass(202908)

Source: CCN
Type: Nextcloud GIT Repository
Files Drop public link can be added as federated share

Source: CONFIRM
Type: Third Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-grph-cm44-p3jv

Source: MISC
Type: Permissions Required, Third Party Advisory
https://hackerone.com/reports/1167929

Source: GENTOO
Type: Third Party Advisory
GLSA-202208-17

Vulnerable Configuration:Configuration 1:
  • cpe:/a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:* (Version < 19.0.11)
  • OR cpe:/a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:* (Version >= 20.0.0 and < 20.0.10)
  • OR cpe:/a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:* (Version >= 21.0.0 and < 21.0.2)

    • Configuration CCN 1:
  • cpe:/a:nextcloud:nextcloud_server:20.0.0:-:*:*:*:*:*:*
  • OR cpe:/a:nextcloud:nextcloud_server:19.0.0:-:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    nextcloud nextcloud server *
    nextcloud nextcloud server *
    nextcloud nextcloud server *
    nextcloud nextcloud server 20.0.0
    nextcloud nextcloud server 19.0.0 -