CVE Vulnerabilities

CVE-2021-32689

Exposure of Sensitive Information to an Unauthorized Actor

Published: Jul 12, 2021 | Modified: Nov 21, 2024
CVSS 3.x
6.5
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS 2.x
4 MEDIUM
AV:N/AC:L/Au:S/C:P/I:N/A:N
RedHat/V2
RedHat/V3
Ubuntu

Nextcloud Talk is a fully on-premises audio/video and chat communication service. In versions prior to 11.2.2, if a user was able to reuse an earlier used username, they could get access to any chat message sent to the previous user with this username. The issue was patched in versions 11.2.2 and 11.3.0. As a workaround, dont allow users to choose usernames themselves. This is the default behaviour of Nextcloud, but some user providers may allow doing so.

Weakness

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

Affected Software

Name Vendor Start Version End Version
Talk Nextcloud * 11.2.2 (excluding)

Extended Description

There are many different kinds of mistakes that introduce information exposures. The severity of the error can range widely, depending on the context in which the product operates, the type of sensitive information that is revealed, and the benefits it may provide to an attacker. Some kinds of sensitive information include:

Information might be sensitive to different parties, each of which may have their own expectations for whether the information should be protected. These parties include:

Information exposures can occur in different ways:

It is common practice to describe any loss of confidentiality as an “information exposure,” but this can lead to overuse of CWE-200 in CWE mapping. From the CWE perspective, loss of confidentiality is a technical impact that can arise from dozens of different weaknesses, such as insecure file permissions or out-of-bounds read. CWE-200 and its lower-level descendants are intended to cover the mistakes that occur in behaviors that explicitly manage, store, transfer, or cleanse sensitive information.

Potential Mitigations

  • Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
  • Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

References