CVE-2021-43825 Use-after-free in Envoy
A use-after-free vulnerability in Envoy proxy allows attackers to cause a denial of service by triggering a crash during buffer overflow handling.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2021-43825?
CVE-2021-43825 is a medium-severity use after free vulnerability in Envoyproxy Envoy, published on 22 Feb 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-416
Which versions are affected by CVE-2021-43825?
1 open source package ship an affected version, including envoy. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
envoy Bitnami | All versions | 1.18.6, 1.19.3, 1.20.2, 1.21.1 |
Products include Envoyproxy Envoy.
How do I fix CVE-2021-43825?
Upgrade envoy to a fixed version for your release line: 1.18.6, 1.19.3, 1.20.2 or 1.21.1.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2021-43825 being exploited?
There is no known exploitation of CVE-2021-43825 in the wild and no public exploit code.
Other vulnerabilities in Envoyproxy Envoy
Sources
Also known as BIT-envoy-2021-43825, GHSA-h69p-g6xg-mhhh.