Is CVE-2021-32778 in the CISA KEV catalog?

No. CVE-2021-32778 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-32778?

CVE-2021-32778 has a CVSS v3 base score of 5.8 (MEDIUM).

What is the EPSS score for CVE-2021-32778?

CVE-2021-32778 has an EPSS score of 1.23% (65th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-32778?

Upgrade envoy to 1.18.4 or later.

CVE & CISA-KEV Catalog

CVE-2021-32778

MEDIUM

5.8

CVSS v3

NVD

Description

Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions envoy’s procedure for resetting a HTTP/2 stream has O(N^2) complexity, leading to high CPU utilization when a large number of streams are reset. Deployments are susceptible to Denial of Service when Envoy is configured with high limit on H/2 concurrent streams. An attacker wishing to exploit this vulnerability would require a client opening and closing a large number of H/2 streams. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes to reduce time complexity of resetting HTTP/2 streams. As a workaround users may limit the number of simultaneous HTTP/2 dreams for upstream and downstream peers to a low number, i.e. 100.

CWE-834

How to fix

Remediation Available

envoyNVD

Affected:>= 1.18.0, < 1.18.4Fixed in:1.18.4CVE-2021-32778derived 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

ScopeChanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

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

Exploit Intelligence

1.23%probability of exploitation in 30 days

65thpercentile

Moderate risk: more likely to be exploited than 65% of all known CVEs.

References

Vendor Advisory1

envoyproxy.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.