High severity · published Jul 12, 2021
CVE-2021-32688
Nextcloud Server is a Nextcloud package that handles data storage
8.8
CVSS
2.3%
EPSS
No
On KEV
Description
Nextcloud Server is a Nextcloud package that handles data storage. Nextcloud Server supports application specific tokens for authentication purposes. These tokens are supposed to be granted to a specific applications (e.g. DAV sync clients), and can also be configured by the user to not have any filesystem access. Due to a lacking permission check, the tokens were able to change their own permissions in versions prior to 19.0.13, 20.0.11, and 21.0.3. Thus fileystem limited tokens were able to grant themselves access to the filesystem. The issue is patched in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds aside from upgrading.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)2.3% · higher than 83% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FE
Fedora · Fedoraproject
33; 34 · source: NVD
NS
Nextcloud Server · Nextcloud
before 19.0.13; 20.0.0 before 20.0.11; 21.0.0 before 21.0.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-32688
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-32688
Third Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-48m7-7r2r-838r
Patch
https://github.com/nextcloud/server/pull/27000
Permissions Required
https://hackerone.com/reports/1193321
lists.fedoraproject.org
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BVZS26RDME2DYTKET5AECRIZDFUGR2AZ/
lists.fedoraproject.org
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J63NBVPR2AQCAWRNDOZSGRY5II4WS2CZ/
Third Party Advisory
https://security.gentoo.org/glsa/202208-17
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