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CVE-2021-21396

6.5 · MEDIUM

wire-server is an open-source back end for Wire, a secure collaboration platform.

Published Mar 26, 2021CWE-200EPSS 1.09%

Overview

CVE-2021-21396 is a medium-severity vulnerability. It was published on March 26, 2021 and has a CVSS 3.1 base score of 6.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

Technical description

wire-server is an open-source back end for Wire, a secure collaboration platform. In wire-server from version 2021-02-16 and before version 2021-03-02, the client metadata of all users was exposed in the `GET /users/list-clients` endpoint. The endpoint could be used by any logged in user who could request client details of any other user (no connection required) as far as they can find their User ID. The exposed metadata included id, class, type, location, time, and cookie. A user on a Wire backend could use this endpoint to find registration time and location for each device for a given list of users. As a workaround, remove `/list-clients` from nginx config. This has been fixed in version 2021-03-02.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/wireapp/wire-server/commit/7ba2bf4140282557cf215e0b2c354d4d08cd3421GitHubgithub.com/wireapp/wire-server/releases/tag/v2021-03-02GitHubgithub.com/wireapp/wire-server/security/advisories/GHSA-qx8q-rhq2-rg4jGitHubgithub.com/wireapp/wire-server/commit/7ba2bf4140282557cf215e0b2c354d4d08cd3421GitHubgithub.com/wireapp/wire-server/releases/tag/v2021-03-02GitHubgithub.com/wireapp/wire-server/security/advisories/GHSA-qx8q-rhq2-rg4j

How CyberStrike helps

Frequently asked questions

What is CVE-2021-21396?

CVE-2021-21396 is a medium-severity vulnerability. It was published on March 26, 2021 and has a CVSS 3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2021-21396?

This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-21396?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-21396?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-21396 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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