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CVE-2021-34823

9.1 · CRITICAL

The ON24 ScreenShare (aka DesktopScreenShare.app) plugin before 2.0 for macOS allows remote file access via its built-in HTTP server.

Published Aug 13, 2021CWE-611EPSS 1.98%

Overview

CVE-2021-34823 is a critical-severity vulnerability. It was published on August 13, 2021 and has a CVSS 3.1 base score of 9.1 (CRITICAL).

This vulnerability has a CVSS 3.1 base score of 9.1, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

The ON24 ScreenShare (aka DesktopScreenShare.app) plugin before 2.0 for macOS allows remote file access via its built-in HTTP server. This allows unauthenticated remote users to retrieve files accessible to the logged-on macOS user. When a remote user sends a crafted HTTP request to the server, it triggers a code path that will download a configuration file from a specified remote machine over HTTP. There is an XXE flaw in processing of this configuration file that allows reading local (to macOS) files and uploading them to remote machines.

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

Refwww.trustwave.com/en-us/resources/security-resources/security-advisories/Refwww.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=29105Refwww.trustwave.com/en-us/resources/security-resources/security-advisories/Refwww.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=29105

How CyberStrike helps

Frequently asked questions

What is CVE-2021-34823?

CVE-2021-34823 is a critical-severity vulnerability. It was published on August 13, 2021 and has a CVSS 3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2021-34823?

This vulnerability has a CVSS 3.1 base score of 9.1, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-34823?

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-2021-34823?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-34823 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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