Is CVE-2021-34823 in the CISA KEV catalog?

No. CVE-2021-34823 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-34823?

CVE-2021-34823 has a CVSS v3 base score of 9.1 (CRITICAL).

What is the EPSS score for CVE-2021-34823?

CVE-2021-34823 has an EPSS score of 1.98% (78th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-34823?

Upgrade screenshare to 2.0 or later.

CVE & CISA-KEV Catalog

CVE-2021-34823

CRITICALEPSS 78th pctl

9.1

CVSS v3

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.

CWE-611XML External Entity (XXE)

How to fix

Remediation Available

screenshareNVD

Affected:< 2.0Fixed in:2.0CVE-2021-34823derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

1.98%probability of exploitation in 30 days

78thpercentile

Elevated risk: more likely to be exploited than 78% of all known CVEs.

References

Third-Party Advisory2

Related Vulnerabilities

Other CWE-611 (XML External Entity (XXE)) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-34102	Critical	9.8	100%	KEV	Fix
CVE-2019-9670	Critical	9.8	100%	KEV	Fix
CVE-2022-28219	Critical	9.8	97%	-	-
CVE-2024-22024	High	8.3	95%	-	-
CVE-2024-38653	High	7.5	92%	-	-
CVE-2017-12629	Critical	9.8	92%	-	Fix

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Markdown

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.