AUGUST 4, 2026
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Case File

CVE-2021-34823

CRITICAL · CVSS 9.1 EPSS 1.98%

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2021-08-13 · Last synced 2026-08-04

CyberRota Analysis

This is a critical severity vulnerability with a CVSS score of 9.1. It may be remotely exploitable.

CVE
CVE-2021-34823
Severity
CRITICAL
CVSS
9.1
EPSS
1.98%

Original NVD 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.