CVE-2021-34823 json
The ON24 ScreenShare (aka DesktopScreenShare.app) plugin before 2.0 for macOS allows remote file access via its built-in HTTP server.
published 2021-08-13 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-21470
- cvss
- 9.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 2.0%
- EPSS 2.0% chance of exploitation in 30 days, percentile 80%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- on24 screenshare 2.0
Exploit prediction
1.98% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| NVD | 2.0 | 6.4 | AV:N/AC:L/Au:N/C:P/I:P/A:N |
Classification
- Weakness
-
- CWE-611 Improper Restriction of XML External Entity Reference
References
-
trustwave.com
/en-us/resources/security-resources/security-advisories/
third-party-advisory
-
trustwave.com
/en-us/resources/security-resources/security-advisories/?fid=29105
third-party-advisory
Sources
- CVE List CVE-2021-34823
- NVD CVE-2021-34823
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