Is CVE-2021-39156 in the CISA KEV catalog?

No. CVE-2021-39156 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-39156?

CVE-2021-39156 has a CVSS v3 base score of 8.1 (HIGH).

What is the EPSS score for CVE-2021-39156?

CVE-2021-39156 has an EPSS score of 1.10% (62th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-39156?

Upgrade istio to 1.11.1 or later.

CVE & CISA-KEV Catalog

CVE-2021-39156

HIGH

8.1

CVSS v3

NVD

Description

Istio is an open source platform for providing a uniform way to integrate microservices, manage traffic flow across microservices, enforce policies and aggregate telemetry data. Istio 1.11.0, 1.10.3 and below, and 1.9.7 and below contain a remotely exploitable vulnerability where an HTTP request with `#fragment` in the path may bypass Istio’s URI path based authorization policies. Patches are available in Istio 1.11.1, Istio 1.10.4 and Istio 1.9.8. As a work around a Lua filter may be written to normalize the path.

CWE-863Incorrect Authorization CWE-706

How to fix

Remediation Available

istioNVD

Affected:>= 1.11.0, < 1.11.1Fixed in:1.11.1CVE-2021-39156derived 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 InteractionRequired

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

1.10%probability of exploitation in 30 days

62ndpercentile

Moderate risk: more likely to be exploited than 62% of all known CVEs.

References

Vendor Advisory1

istio.io

Third-Party Advisory1

github.com

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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.