Is CVE-2022-21656 in the CISA KEV catalog?

No. CVE-2022-21656 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2022-21656?

CVE-2022-21656 has a CVSS v3 base score of 7.4 (HIGH).

What is the EPSS score for CVE-2022-21656?

CVE-2022-21656 has an EPSS score of 0.77% (51th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2022-21656?

Upgrade envoy to 1.20.2 or later.

CVE & CISA-KEV Catalog

CVE-2022-21656

HIGH

7.4

CVSS v3

NVD

Description

Envoy is an open source edge and service proxy, designed for cloud-native applications. The default_validator.cc implementation used to implement the default certificate validation routines has a "type confusion" bug when processing subjectAltNames. This processing allows, for example, an rfc822Name or uniformResourceIndicator to be authenticated as a domain name. This confusion allows for the bypassing of nameConstraints, as processed by the underlying OpenSSL/BoringSSL implementation, exposing the possibility of impersonation of arbitrary servers. As a result Envoy will trust upstream certificates that should not be trusted.

CWE-295Improper Certificate Validation CWE-843Type Confusion

How to fix

Remediation Available

envoyNVD

Affected:< 1.20.2Fixed in:1.20.2CVE-2022-21656derived 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 ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

0.77%probability of exploitation in 30 days

51stpercentile

Moderate risk: more likely to be exploited than 51% of all known CVEs.

References

Patch1

github.com

Third-Party Advisory1

github.com

Related Vulnerabilities

Other CWE-295 (Improper Certificate Validation) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2015-4000	Low	3.7	100%	-	Fix
CVE-2020-0601	High	8.1	89%	KEV	Fix
CVE-2009-3555	Critical	9.8	87%	-	Fix
CVE-2022-26923	High	8.8	83%	KEV	Fix
CVE-2023-27823	Critical	9.8	53%	-	-
CVE-2022-42979	High	8.8	24%	-	-

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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.