CVE-2021-43825

Name: CVE-2021-43825
Creator: NVD / NIST
Published: 2022-02-22T23:15:10.89+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.86%

Last modified Jun 17, 2026

CVE-2021-43825 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Envoy is an open source edge and service proxy, designed for cloud-native applications. Sending a locally generated response must stop further processing of request or response data. EPSS estimates a 0.86% chance of exploitation in the next 30 days.

Description

Envoy is an open source edge and service proxy, designed for cloud-native applications. Sending a locally generated response must stop further processing of request or response data. Envoy tracks the amount of buffered request and response data and aborts the request if the amount of buffered data is over the limit by sending 413 or 500 responses. However when the buffer overflows while response is processed by the filter chain the operation may not be aborted correctly and result in accessing a freed memory block. If this happens Envoy will crash resulting in a denial of service.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

0.86%

54.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-416

Affected Software

Vendor	Product	Versions
Envoyproxy	Envoy	< 1.18.6
Envoyproxy	Envoy	>= 1.19.0, < 1.19.3
Envoyproxy	Envoy	>= 1.20.0, < 1.20.2
Envoyproxy	Envoy	>= 1.21.0, < 1.21.1

References

https://github.com/envoyproxy/envoy/commit/148de954ed3585d8b4298b424aa24916d0de6136Patch, Third Party Advisory
https://github.com/envoyproxy/envoy/security/advisories/GHSA-h69p-g6xg-mhhhIssue Tracking, Third Party Advisory
https://github.com/envoyproxy/envoy/commit/148de954ed3585d8b4298b424aa24916d0de6136Patch, Third Party Advisory
https://github.com/envoyproxy/envoy/security/advisories/GHSA-h69p-g6xg-mhhhIssue Tracking, Third Party Advisory

Timeline

Published: Feb 22, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-43825?

How severe is CVE-2021-43825?

CVE-2021-43825 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.86% probability of exploitation in the next 30 days.

How do I fix CVE-2021-43825?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-43825?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST