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CVE-2021-34823

CRITICALCVSS 9.1/10EPSS 1.98%

Last modified

CVE-2021-34823 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. 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. EPSS estimates a 1.98% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
9.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS Probability
1.98%

78.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
On24Screenshare< 2.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-34823?
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.
How severe is CVE-2021-34823?
CVE-2021-34823 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 1.98% probability of exploitation in the next 30 days.
How do I fix CVE-2021-34823?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-34823?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST