How severe is CVE-2020-35471?

CVE-2020-35471 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-35471 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-35471?

CVE-2020-35471 affects Envoyproxy Envoy. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-35471?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-35471 published?

CVE-2020-35471 was published on 2020-12-15 and last updated on 2026-06-17.

CVE-2020-35471

CVE-2020-35471 is a high-severity vulnerability in Envoyproxy Envoy with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Envoyproxy Envoy
Published: 2020-12-15
Last modified: 2026-06-17

Description

Envoy before 1.16.1 mishandles dropped and truncated datagrams, as demonstrated by a segmentation fault for a UDP packet size larger than 1500.

Frequently asked questions

What is CVE-2020-35471?: Envoy before 1.16.1 mishandles dropped and truncated datagrams, as demonstrated by a segmentation fault for a UDP packet size larger than 1500.
How severe is CVE-2020-35471?: CVE-2020-35471 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-35471 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-35471?: CVE-2020-35471 affects Envoyproxy Envoy. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-35471?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-35471 published?: CVE-2020-35471 was published on 2020-12-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*

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