Is CVE-2021-31921 in the CISA KEV catalog?

No. CVE-2021-31921 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-31921?

CVE-2021-31921 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2021-31921?

CVE-2021-31921 has an EPSS score of 1.45% (70th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-31921?

Upgrade istio to 1.9.5 or later.

CVE & CISA-KEV Catalog

CVE-2021-31921

CRITICALEPSS 70th pctl

9.8

CVSS v3

NVD

Description

Istio before 1.8.6 and 1.9.x before 1.9.5 contains a remotely exploitable vulnerability where an external client can access unexpected services in the cluster, bypassing authorization checks, when a gateway is configured with AUTO_PASSTHROUGH routing configuration.

CWE-862Missing Authorization

How to fix

Remediation Available

istioNVD

Affected:>= 1.9.0, < 1.9.5Fixed in:1.9.5CVE-2021-31921derived 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

AvailabilityHigh

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

Exploit Intelligence

1.45%probability of exploitation in 30 days

70thpercentile

Elevated risk: more likely to be exploited than 70% of all known CVEs.

References

Exploit1

istio.io

Related Vulnerabilities

Other CWE-862 (Missing Authorization) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2021-39226	Critical	9.8	100%	KEV	Fix
CVE-2022-0543	Critical	10.0	100%	KEV	Fix
CVE-2021-21978	Critical	9.8	99%	-	Fix
CVE-2023-52163	High	8.8	96%	KEV	-
CVE-2022-1329	High	8.8	93%	-	-
CVE-2023-6875	Critical	9.8	90%	-	-

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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.