Is CVE-2021-43826 in the CISA KEV catalog?

No. CVE-2021-43826 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-43826?

CVE-2021-43826 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2021-43826?

CVE-2021-43826 has an EPSS score of 1.05% (60th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-43826?

Upgrade envoy to 1.21.1 or later.

CVE & CISA-KEV Catalog

CVE-2021-43826

HIGH

7.5

CVSS v3

NVD

Description

Envoy is an open source edge and service proxy, designed for cloud-native applications. In affected versions of Envoy a crash occurs when configured for :ref:`upstream tunneling <envoy_v3_api_field_extensions.filters.network.tcp_proxy.v3.TcpProxy.tunneling_config>` and the downstream connection disconnects while the the upstream connection or http/2 stream is still being established. There are no workarounds for this issue. Users are advised to upgrade.

CWE-416Use After Free

How to fix

Remediation Available

envoyNVD

Affected:>= 1.21.0, < 1.21.1Fixed in:1.21.1CVE-2021-43826derived 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

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

1.05%probability of exploitation in 30 days

60thpercentile

Moderate risk: more likely to be exploited than 60% of all known CVEs.

References

Patch1

github.com

Third-Party Advisory1

github.com

Related Vulnerabilities

Other CWE-416 (Use After Free) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2019-0708	Critical	9.8	100%	KEV + Ransom	-
CVE-2021-31166	Critical	9.8	100%	KEV	Fix
CVE-2015-5119	Critical	9.8	99%	KEV	-
CVE-2010-3962	High	8.1	97%	KEV	-
CVE-2015-0313	Critical	9.8	96%	KEV	Fix
CVE-2017-9798	High	7.5	95%	-	Fix

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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.