CVE-2021-32688

Application specific tokens can change their own scope

HIGH
8.8
CVSS Score
Published: July 12, 2021 at 01:45 PM UTC
Updated: June 17, 2026 at 03:53 AM UTC
2 products affected across 2 vendorsFedoraNextcloud/server

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Severity
HIGH8.8
Exploit prediction
EPSS 2%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 19.0.1320.0.0 ≤ v < 20.0.1121.0.0 ≤ v < 21.0.3
Affected range stops below 19.0.13, so it looks safe — our inference, not a vendor statement
Affected range stops below 20.0.11, so it looks safe — our inference, not a vendor statement
Affected range stops below 21.0.3, so it looks safe — our inference, not a vendor statement

CVSS

8.8HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-285CWE-552

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