Is CVE-2021-31920 in the CISA KEV catalog?

No. CVE-2021-31920 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-31920?

CVE-2021-31920 has a CVSS v3 base score of 6.5 (MEDIUM).

What is the EPSS score for CVE-2021-31920?

CVE-2021-31920 has an EPSS score of 1.17% (64th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-31920?

Upgrade istio to 1.9.5 or later.

CVE & CISA-KEV Catalog

CVE-2021-31920

MEDIUM

6.5

CVSS v3

NVD

Description

Istio before 1.8.6 and 1.9.x before 1.9.5 has a remotely exploitable vulnerability where an HTTP request path with multiple slashes or escaped slash characters (%2F or %5C) could potentially bypass an Istio authorization policy when path based authorization rules are used.

CWE-706

How to fix

Remediation Available

istioNVD

Affected:>= 1.9.0, < 1.9.5Fixed in:1.9.5CVE-2021-31920derived 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 RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

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

Exploit Intelligence

1.17%probability of exploitation in 30 days

64thpercentile

Moderate risk: more likely to be exploited than 64% of all known CVEs.

References

Exploit1

istio.io

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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.