CVE-2021-43825

CVE-2021-43825 is a medium-severity vulnerability in Envoyproxy Envoy with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

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.

Frequently asked questions

What is CVE-2021-43825?
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.
How severe is CVE-2021-43825?
CVE-2021-43825 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability low.
Is CVE-2021-43825 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43825?
CVE-2021-43825 affects Envoyproxy Envoy. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43825?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-43825 published?
CVE-2021-43825 was published on 2022-02-22 and last updated on 2026-06-17.

References

Affected products (1)

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