Vulnerability Name:

CVE-2021-22915 (CCN-203594)

Assigned:2021-06-01
Published:2021-06-01
Updated:2021-09-20
Summary:Nextcloud server before 19.0.11, 20.0.10, 21.0.2 is vulnerable to brute force attacks due to lack of inclusion of IPv6 subnets in rate-limiting considerations. This could potentially result in an attacker bypassing rate-limit controls such as the Nextcloud brute-force protection.
CVSS v3 Severity:9.8 Critical (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
8.5 High (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): High
Availibility (A): High
5.3 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N)
4.6 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): Low
Availibility (A): None
CVSS v2 Severity:5.0 Medium (CVSS v2 Vector: AV:N/AC:L/Au:N/C:P/I:N/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (Au): None
Impact Metrics:Confidentiality (C): Partial
Integrity (I): None
Availibility (A): None
5.0 Medium (CCN CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:P/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): Partial
Availibility (A): None
Vulnerability Type:CWE-307
Vulnerability Consequences:Bypass Security
References:Source: MITRE
Type: CNA
CVE-2021-22915

Source: XF
Type: UNKNOWN
nextcloud-cve202122915-brute-force(203594)

Source: CCN
Type: Nextcloud GIT Repository
Ratelimiting can be bypassed using IPv6 subnets

Source: CCN
Type: Hackerone #1154003
Nextcloud server

Source: MISC
Type: Permissions Required, Third Party Advisory
https://hackerone.com/reports/1154003

Source: FEDORA
Type: Mailing List, Third Party Advisory
FEDORA-2021-afa7968aeb

Source: FEDORA
Type: Mailing List, Third Party Advisory
FEDORA-2021-eac0e52f88

Source: MISC
Type: Broken Link
https://nextcloud.com/security/advisory/?id=NC-SA-2021-009

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 2:
  • cpe:/o:fedoraproject:fedora:33:*:*:*:*:*:*:*
  • OR cpe:/o:fedoraproject:fedora:34:*:*:*:*:*:*:*

  • Configuration CCN 1:
  • cpe:/a:nextcloud:nextcloud_server:20.0.0:-:*:*:*:*:*:*
  • OR cpe:/a:nextcloud:nextcloud_server:19.0.0:-:*:*:*:*:*:*
  • OR cpe:/a:nextcloud:nextcloud_server:21.0.0:-:*:*:*:*:*:*

  • * Denotes that component is vulnerable
    BACK
    nextcloud nextcloud server *
    nextcloud nextcloud server *
    nextcloud nextcloud server *
    fedoraproject fedora 33
    fedoraproject fedora 34
    nextcloud nextcloud server 20.0.0
    nextcloud nextcloud server 19.0.0 -
    nextcloud nextcloud server 21.0.0 -